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Tests

ABR

What is a CM?
The CM (cochlear microphonic) is a response from the cochlea that mimics the input stimulus and is believed to be a response primarily from the outer hair cells (Dallos, 1983).

Why CM?
The presence of a CM along with an absent or abnormal ABR is used in the diagnosis of auditory neuropathy spectrum disorder (ANSD). When a click ABR or CE-Chirp® perform a CM test. Determining the presence or absence of the CM (OHC response) is an important part of the ANSD test battery.

How to test
Patient Preparation is very important. The patient should be relaxed or sleeping in a quiet environment and lying down during the procedure.

Electrode Placement: It is possible to obtain CM from with a standard ABR electrode montage, however the strongest signal will be obtained with electrodes positioned from a point as close to the site of generation as possible. The most commonly used electrodes for this purpose are the gold foil TipTrodes or TM-trodes. Below are two examples of electrode placements 1) Electrode placement using EPA4 with a TM-trode, and 2) Electrode placement using EPA3 and with a TM-trode.

For both examples the TM-trode and the test ear must be prepared prior to placing the TM-trode on the TM. To reduce impedance a solution of saline can be used. Drain the ear prior to inserting the TM-trode. The TM-trode can be placed in a saline solution for a few minutes prior to placing it on the TM and should be dipped in electrode contact gel (e.g. Sonaville) prior to placing it at the TM.

Example of electrode placement using the TM-trode and EPA4

Example of electrode placement using EPA3 and with a TM-trode electrode

The EPA3 is a simple alternative when only 1-channel is desired and using the TM-trode

Transducer selection: Insert phones must be used, as they allow you to perform a baseline of the recordings. This is done by clamping or pinching the insert phone silicone tubes and then measuring the response. This eliminates the stimuli to the patient’s ears allowing you to distinguish electrical artifacts from a true CM response.

Note the transducers should be placed away from the measurement electrodes and its cables.

Setting up the Eclipse
The Eclipse comes with a pre-programmed protocol for CM testing (license) so the system is ready to use immediately. Protocols can be created or modified easily to fit your clinic needs. Consult your Eclipse Additional Information to learn how to create or modify a protocol. The procedure described below is a guideline for CM testing.

CM test procedure

  1. Choose the protocol Coclear Microphonics CM 

  2. Press  in the toolbar menu to enable A/B (condensation (+) and rarefaction (-)).
    Alternatively, if you want to measure one curve as condensation and one curve as rarefaction enter the Temporary Setup prior to starting the test to change the polarity.

  3. Perform a baseline measure with the tube clamped. Make sure not to move the transducer when doing so.

  4. Select ear and intensity and start the measure. Clicks at the intensity level of 80-85dB nHL should be used.

  5. Monitor the EEG during testing to assure a collection with minimal noise.

  6. Monitor the response on the screen in the first few milliseconds – typically 2000 sweeps are conducted when measuring with the A/B enabled using an alternating stimuli – though the number of sweeps should not be used as stop criteria on its own.

  7. If a CM is present it is important to ensure that it is not a stimulus artifact. Make sure that the measure is reproducible and run a measure with the tube clamped.

 

CM result
Below are two examples of CM responses. The upper is a case of ANSD, while the lower is measured on an individual with normal cochlear microphonic function.

The upper example shows a CM of a baby with ANSD, showing rarefaction, condensation and base line with tube clamped (Stevens et al, 2011).The lower example shows a CM from an infant considered normal.

Patients with ANSD show an abnormal CM, seen as greater than normal amplitude of the response within the first milliseconds. In addition the latency of the CM duration is often longer than expected. Please note that the CM response itself is not sufficient documentation for ANSD and must be supported with an ABR recording to examine if the ABR response is present or absent.

Reporting
Choose the Report Icon 
When complete, choose Save and Exit


References
Dallos P. (1983) Some electrical circuit properties of the organ of Corti. I. Analysis without reactive elements. Hear Res;12:89-120.

Stevens et al. (2011) Guidelines for Cochlear Microphonic Testing, NHS v. 2.0 Edited 2014.

July 2016

What is ALR / Cortical ERA?
Auditory Late Responses (ALRs) are longer latency components that for most part are generated in higher regions of the auditory CNS, including the auditory cortex. Cortical Evoked Response Audiometry (CERA) refers to the technique of measuring ALRs for the purpose of assessing ones hearing abilities. The responses are typically measured using surface electrodes placed on the scalp of an individual.

Why ALR?
ALR/Cortical ERA is traditionally used to help determine the degree of hearing loss in adult populations. Compared to traditional Auditory Brainstem Responses (ABRs), or behavioral audiometry, ALRs demonstrate audibility at the cortex without the need for the listener to play an active role in the procedure. This is a key advantage in various medico-legal scenarios or in cases where the individual is unable or unwilling to provide accurate behavioral responses to a sound.
Other advantages include the relative robustness of the ALRs to myogenic activity, the high frequency specificity of the tonal stimuli due to their longer duration, and is much closer to the behavioral audiometric pure tone compared to traditional ABR octave wide stimuli, and the ability to calibrate the stimuli according to international standards (BS EN ISO 389 as for pure tone audiometers) and not the standard 389-6 used for Tone burst/Tone pips & Chirps .
The key ALR waveforms observed in CERA are the P1, N1, and P2 responses. The ALR latency typically ranges from 50 – 300 ms and N1-P2 amplitude ranges from 0-20 μV. (see Figure 1, showing P1, N1 and P2 responses to a 2 kHz toneburst stimuli, used to provide a typical threshold recording from the left ear. In this case, hearing sensitivity is shown to be within the normal audiometric range.)

Figure 1 ALR responses Right and Left

How to test
Patient Preparation
is very important. Patient arousal and attention state has a significant effect on the amplitudes of the ALR. The ALR waveform changes as a person becomes drowsy or falls asleep. When a patient is asleep the N1 amplitude is smaller and the P2 amplitude is larger. However, when the subject is listening for a change or paying close attention to stimuli the N1 increases in amplitude and in subjects who are not attending to the stimuli, the N1 can become difficult to measure at low intensities (Näätänan and Picton, 1987). The response also habituates quickly, an affect which is more apparent nearer to the threshold of the listener, so it is important to limit the number of stimulus presentations within each ‘run’. Typically, between 15 and 20 presentations might be made per run and a number of successive runs are then merged into a grand average in order to reveal the ALR.
The patient is typically instructed to sit quietly during the procedure, maintaining passive attention for example by reading or watching a close-caption movie with the sound muted. It is not advised to perform ALR and under sedation (Crowley & Colrain, 2004).

Electrode Placement:
It is possible to obtain ALR with a standard 2-channel electrode montage, with an active vertex electrode referenced to either right or left mastoid. However, since the ALR has generators orientated towards the fronto- central regions of the scalp then response strength may be greater when recorded from a point on the midline that is slightly forward of the vertex position.

Setting up the Eclipse
The Eclipse comes with a pre-programmed protocol for ALR testing (license), and is ready for immediate use. Protocols can be created or modified easily to fit your clinic needs. Consult your Eclipse Additional Information to learn how to create or modify a protocol.

Protocol Settings:
In CERA, ALRs should be measured using tone burst (250 Hz – 4 kHz) stimuli at intensity levels between 0 and 100 dB HL to establish threshold.

Summary of parameters for ALR 

    P1, N1, P2
Subject State Awake and quit adults, (and older children)
Eyes Eyes open
Condition Attend or ignore conditions
Stimuli  Recordings Types of stimuli Tone burst, speech vowels or consonant vowel combinations
Inter-onset interval 1-2 sec
Stimulus duration  50 – 80 ms (including 10-15 ms onset/offset ramps)
Presentation  Typically insert or supra-aural headphones
Intensity Starting at 60-80 dB HL
Recordings Reference electrode Right/Left mastoid (optimally linked electrodes using the jumper cable)
Filtering 1-30 Hz
Analysis time Pre stimuli -100ms
Post stimuli 700ms or more
Sweep 50-300 [comprised of 10-20 sweep sub averages]
Waveform reproducibility Set within the latency range 30 –270 ms
Measurements Adult
Children
Infants
Measures 
P1, N1, P2
P1, N200-250
Reliable components
Baseline to peak amplitude, peak latency
Use latency window established using grand mean data
Response presence   Determined by   Replicable components
Response amplitude should be ≥ 2.5 times larger than the residual noise.
Residual noise amplitude should be < 1.5 μV (as determined by average difference between replicates)

Interpretation of the ALR result
Typically the ALR threshold recording is started at 60dB HL and increased or decreased by 20dB based on the response. 5 or 10 dB steps are typically used when close to threshold.

It is recommended that the amplitude of the response is taken as the peak-to-peak amplitude between N1 and P2, and a lower value of 2.5 μV is recommended before a response can be clearly identified. The Waveform Reproducibility function can also be used to indicate the response reliability. This function provides a measure of the correlation between curves held in the A and B buffer when there is a response present.

The residual noise in the trace can be estimated by measuring the ‘average gap’ between replicates (for example, between rarefaction and condensation responses displayed in the A-B buffer).

See Figure 2, which shows the A and B curves separate for each trace. Over the duration of the epoch (-150 ms to + 750 ms) the average gap between traces can be observed to be below 1 μV, and the Waveform Reproducibility for the highlighted curve is shown to be high (73%) indicating reliable response.

Figure 2 ALR showing A&B buffer for repeatability

Electrophysiological Threshold Estimation and correction factors
An ALR threshold at 20dBHL at 2kHz would be considered within the range of normal hearing. Applying a typical correction factor would estimate the behavioral threshold to be 13.5dBHL at 2 kHz.
For masking the ALR, please follow the pure tone audiometry guidance’s.

Lowest level response >5uV: interpolate
Lowest level response <5uV: is threshold

ALR threshold behavioral correction factors to estimated hearing thresholds.

  500Hz 1000Hz 2000Hz 4000Hz
Stimuli (dB HL) 50 60 65 65
Mean Correction (dB)* -6.5 -6.5 -6.5 -6.5
d(B) estimated hearing level eHL 43.5 53.5 58.5 58.5

*Reportings from Liverpool UK, Variance 95% within ±10dB. Note occasionally very poor response > 20dB error

Reporting
Choose the Report Icon

When complete, choose Save and Exit.


References
Crowley, K.E. & Colrain, I.M. (2004) A review of the evidence for P2 being an independent component process: age, sleep and modality. Clin Neurophysiol.(115(4) 732-44.

Näätänen, R. & Picton, T. (1987) The N1 wave of the human electric and magnetic response to sound: A review and an analysis of the component structure. Soc. For Psychophysiological Research, Inc. 24 (4) 375-425.

October 2015

What is AMLR?
Auditory Middle-Latency Responses (AMLR) are related to auditory generators of the subcortical regions Na and Pa components at cortical levels. Na is considered the onset of the AMLR and Pa is considered the most robust component of the AMLR.

Why AMLR?
AMLR has the potential to offer a more complete picture of the status of the auditory system and can be used to help determine the degree of hearing loss. The most common neurological use of the AMLR is for the assessment of the functional integrity of the auditory pathway above the level of the brainstem in cases with suspected lesions and for the assessment of nonorganic hearing loss.

Further, AMLR is used in instances of traumatic brain injury, cortical deafness, multiple sclerosis, and cases of central auditory processing disorders.

Young children and infants may not present AMLR even when their auditory and neurological functions are intact, because of their higher sensitivity to stimulus rate. In general AMLR from children younger than 10 years should be interpreted with caution. It is also important to note that prior to the level of interest the auditory function should be examined and working normally, if not this will affect the AMLR results.

The stimuli used for AMLR is similar to the traditional ABR octave wide stimuli.

How to test
Patient Preparation is very important. The patient is instructed to relax and informed about the test procedure prior to testing. AMLR’s are most reliable when the patient is awake and quiet.

During sedation as with natural sleep the ALMR response is not affected.

Electrode Placement:
It is possible to obtain AMLR from with a standard ABR electrode montage. Due to the latency of the AMLR measurement, it is important to pay attention to the PAM muscle artifact, so it is not misinterpreted as an AMLR. To minimize the influence of the PAM muscle, ensure that the patient is calm and relaxed and place the electrodes on the earlobe rather than on the mastoid.

Setting up the Eclipse
The Eclipse comes with a pre-programmed protocol for AMLR testing (license) and is ready to use immediately. Protocols can be created or modified easily to fit your clinic needs. Consult your Eclipse Additional Information to learn how to create or modify a protocol.

Protocol settings:

  • An AMLR should be measured using traditional ABR stimuli, such as Toneburst 250Hz – 4kHz, stimuli from the CE-Chirp® LS family or custom wave files at an moderate intensity level.
  • For neuro diagnosis a moderate stimuli intensity below 70dB nHL is appropriate.
  • For threshold estimation, present stimuli levels as done with traditional ABR threshold testing.
  • A slower rate is indicated for younger children or for patients with cortical pathology. Normal rate for adults is below 7.1 stimuli per second.
  • Stimuli rates as low as 1 per second or 0.5 per second are required to consistently record the Pb component.

Interpretation of the AMLR result
The AMLR latency ranges from 15-80 ms and amplitude sizes ranges from 0-2uV.

An AMLR threshold recording here using Tone Burst 1kHz for threshold evaluation.

Cochlear implants
The longer latencies of the AMLR separate them from the cochlear implant stimuli artifacts seen under the traditional eABR. Therefore AMLR’s may be used to assess the efficacy of cochlear implants in activating the auditory pathway.

Reporting
Choose the Report Icon .
When complete, choose Save and Exit.


References 
Atcherson, S.R. & Kennett, S.W. (2013), Applications of middle and late latency responses, ENT & Audiology news (20)4.

Roeser, R.J., Valente, M., Hosford-Dunn, H. (2007). Audiology Diagnosis, Theime 2nded

July 2016

What is Residual Noise?

  •  It is the averaged background noise.

    How does it Work?
  • It is calculated online during the ABR recording by measuring the stability of the averaged waveform.
  • The residual noise calculation used for Fmp is the same used for the calculation of Residual Noise - typically in a time window of 10ms.
  • The greater the stability, the less noise in the tracing.
  • When the Residual Noise level reaches the set criteria, e.g. 40nV for adults and 20nV for children, the residual noise bar turns green with a checkmark.

What is Fmp?

  • It is a statistical online analysis of the ABR recording from beginning to end.
  • The Response Confidence is a statistical confidence of a true detection of a response, by default 99% (Fmp 3.1).

    How does it Work?
  • It works on the principle of comparing response amplitude to residual noise to provide confidence level or detection rate.
  • The underlying analysis considers the ABR recording typically in a time window of 10ms.
  • The Fmp ratio between the response amplitude and the residual noise is calculated.
  • In a response situation, lower noise or larger response amplitude will drive the Fmp up (indicated by the red line and bar).
  • In a no-response situation, the response amplitude will not rise above the residual noise, thus the Fmp value and the Response Confidence will remain low.

    What is the benefit of calculating Fmp?
  • The calculation provides statistical documentation and support of the findings.
  • Acts as a Quality Meter for the waveform.

Benefits of Fmp and Residual Noise

  • Low residual noise levels mean there is less noise in the tracing.
  • Less noise in the tracing improves confidence when eyeballing the presence or absence of a response.
  • It is unlikely that continued averaging with noise levels below 40nV for adults and 20nV for children will result in a response becoming visible, so residual noise may be used as stop criteria in no-response situations.

Clinical benefits

  • Improves confidence in a presence or absence of the response.
  • Can reduce test time.
  • Relies on statistical data not solely on the experience of the user in determining the presence or absence of the response.

References 
Don, M. & Elberling, C. (1996). Use of quantitative measures of auditory brain-stem response peak amplitude and residual background noise in the decision to stop averaging. J. Acoust. Soc. Am., 99(1).

Elberling, C. & Don, M. (1984). Quality Estimation of averaged auditory brainstem responses. Scand Audiol., (13) 187-197.

July 2016

Several things can influence the results obtained during ABR / ABRIS / ASSR testing. In this guide, some hints for improved recordings will be described. All the suggestions listed below can be applied to the ABR, ABRIS and ASSR module.

Skin Preparation and Electrodes

1. Preparing the skin
Always use an abrasive preparation gel (e.g., NuPrep) to ensure that the top layer of skin (epidermis) is cleaned and oil is removed. The skin may become a little red after an appropriate preparation, and you should aim to get impedances below 3kOhm.

Note Be careful not to damage the skin.

Neonates Some clinicians use only alcohol wipes/pads to remove vernix prior to ABR recording on neonates (age 0-3 months). A disinfectant agent such as alcohol can also be used for preparing the skin of neonates.

Preparation instructions: Remove any oil/lotion/vernix from the contact point on patient’s head. Wipe all preparation gel off with an alcohol wipe/pad or a soft dry non-stick cloth (e.g., gauze).

  • For sensitive/allergic skin, it may be best to use only a soft dry cloth since alcohol can dry out the skin. If the patient suffers from any known allergies e.g., perfume, pay extra attention to the use of disinfectant agents.
  • Since alcohol may take time to dry, impedances may be slightly higher when using alcohol. Make sure that the alcohol is completely dry before applying conductive gel and electrodes.
  • Some clinicians prefer not to use alcohol pads/disinfectant agents, but remove the preparation gel with a dry non-stick cloth (e.g., gauze).
  • If the patient’s skin is dry or you are obtaining high impedances, apply a small amount of conductive gel/paste to the skin prior to connecting the surface electrode. This will help to rehydrate the skin and to lower impedances.

2. Mounting the electrodes
Always prepare the skin prior to mounting either disposable or reusable electrodes.
Some disposable electrodes are pre-gelled (e.g., PEG15), and no further gel is required.

Note When mounting pre-gelled disposable electrodes (e.g., PEG15), do not press in the middle of the electrode as gel to be dispersed to the adhesive outer edge causing the electrode to loosen from the skin, causing very high impedances during testing.

  • Mount the disposable electrode by pressing down around the adhesive outer edge.
  • If you gently pull on the electrode a few seconds after application, the electrode should remain tightly adhered to the skin. This should ensure very low impedances (≤ 1kOhm).
  • Recommended impedance are below or equal to 3kOhms and balanced (e.g., all electrodes should have similar impedance values within 2kOhms).

Reusable electrodes are expected to have higher impedance than the disposable electrodes.

  • For reusable electrodes, it should be possible to achieve impedances in the range of 1-5kOhms.
  • Always apply a conductive electrode gel/paste (e.g., 10-20 paste) to all reusable electrodes before mounting.
  • Use medical tape (e.g., micropore) to hold the reusable electrode cups in place on the skin.

Lead is sometimes soldered onto the reusable cup electrodes by a hospital to improve their conductivity; producing lower impedances. Reusable electrodes containing lead are not supplied, because of the hazardous nature of lead

Reducing Noise

1. Test Room Parameters
The test room and location of the room can greatly effect ABR recordings.

The following test room parameters should be aimed for:

  • A magnetically shielded booth/room (if possible).
  • A quiet or soundproofed booth or sound treated room. This ensures the patient can relax without disturbances and the stimulus noise is not masked by background noise.
  • Use of a dedicated ground (isolated socket) for the ABR equipment.
  • Lights and other equipment not being used should be turned off or unplugged as the patient can work as an antenna and picks up electrical interference from these sources.
  • Separate equipment cables to reduce interference (e.g., braid electrode cables, keep electrode cables and transducer cables away from each other).

In some cases, it may be necessary to find another test location if there is too much ambient or electrical noise in the current test room. 
Try moving the test bed within the room. It may be placed unknowingly, adjacent to a wall that has hidden cables and electrical sources.

2. Patient Instructions
The quality of the ABR recordings depends highly on the state of the patient. If the patient is not physically/mentally relaxed, more unstable, noisy recordings will be seen.

Instruct the patient so that:

  • They are relaxed and calm.
  • Their eyes are closed and that their face and jaw muscles are relaxed.
  • They are lying down on a comfortable bed or reclining in a comfortable chair. The duration of an ABR test can be long, so ensure that the patient is as comfortable as possible (use pillows and blankets as needed).

    Note An upright sitting position should be avoided due to contracted neck/head muscles.

  • Turn off lights in the test room to avoid electrical interference and to help the patient to relax/go to sleep. Sleeping during recording will provide the lowest noise from the patient, so a sleeping state is preferred if possible.
  • Test infants and children during sleep is recommended as they cannot be instructed to or find it difficult to relax for the entire test duration.

It is important to try and use the same test conditions and parameters for each test when comparing results.

3. Set an appropriate rejection level

  • A recording cannot be collected if the system rejects the signal.
  • Adjust the rejection level to an appropriate level according to the patient and test type. Typically, ABR recordings can be made using a rejection level of 40μV or less when the patient is relaxed and/or sleeping.
  • A lower rejection level means a lower amount of noise is recorded during each average. This equates to faster and more accurate recordings.

Changing the rejection level
The rejection level should be increased until the real time EEG signal (top of the screen) is no longer red (indicating rejection). The rejection level used will depend on the patient and the electrical interference in the test room. A black EEG curve indicates that the system is ready to measure.

The higher the rejection level value, the more noise is recorded during each average. Therefore, always use the lowest possible rejection level value, without rejection. The level can be adjusted during a recording, by double clicking on the EEG window (EP15/25 only) and adjusting the input level by dragging the horizontal bars.

If a high rejection setting is needed, check that electrode impedances are sufficiently low and that the patient is relaxed before starting the test. Muscle tension of the face, back or neck due an uncomfortable or incorrect position will disturb the ABR recordings as these muscles are close to the recording site.

4. Use of a Ground
Grounding is crucial for good ABR waves and safe operation. A separate ground dedicated for the ABR equipment should be used. A true ground uses a minimum of three earth rods.

The Eclipse’s power cord contains a ground lead (typically indicated by yellow and green colors), but often the ground at the test site may not be sufficient.

  • Always check the wall outlet for a proper ground when establishing an ABR test room. Sometimes the ground lead is found inside the wall outlet, but is not connected to the ground. In these cases where the ground is not connected or even missing, the ABR recordings will be dramatically distorted.
  • Electrical interference may appear through the ground lead if the wall outlet used is connected to a shared ground (e.g., other wall outlets with electrical equipment connected share the ground). In this case, a dedicated ground wall outlet for the ABR recording equipment should be established.
  • The ABR system cabinet is connected to the ground lead via an internal capacitor. If the ground lead is not connected, the ABR system will pick up electrical noise/interference. This will be seen on the screen as very large harmonic distortion curves completely overlaying/destroying the ABR curves.
  • Ground the patient bed if it is made of metal. On the backside of the Eclipse, there is a special ground plug which can be connected to the patient bed.

Check the ground for proper and correct function
Due to High Voltage, only experienced technicians/ properly trained staff must check and change the ground.

To check and verify the ground, various methods can be used.

  1. Adedicatedgroundtester.
  2. Avoltage/impedancecomparisonfromthewalloutletgroundleadtoatriangleofearthrods.
  3. Ground should have max 8ohm, and 0.5V deviation compared to the true ground.
  4. A more simple check is to use a Voltage Meter and measure directly from the wall outlet. Please verify these specifications:
    1. The Voltage between Phase (Hot) socket and Zero (Neutral) socket must be a stable 230V for Europe /110V for US (country specific).
    2. Check the Voltage between phase (Hot) socket and Ground socket, 230V for Europe / 110V for US (country specific). The voltage value found in step a, should match the voltage value found in this step (within 5V). If the recorded voltage is much less than the expected voltage (e.g., a voltage reading of 50V for US), the ground is not connected to a true ground, even though you may be able to see the lead in the wall.
    3. Check the Voltage between Zero (Neutral) and Ground. It must be 0V. If the recorded voltage is much less than the expected voltage, the ground is not connected to a true ground, even though you may be able to see the lead in the wall.

Reducing noise in the EP15/25 module

1. Optimizing Settings
Changing the filter settings can reduce excessive environmental electrical interference.

With the EP software, go to File - System setup – Auto Protocols tab.
For 15ms tests (ABR-15), change the high pass filter to “100Hz 12/oct”.

Note Using a filter setting like this may reduce the amplitude in the ABR waveforms. However it may be needed if it is impossible to obtain ABR curves without excessive electrical interference.

Change the stimulus rate so that it isn’t time locked to other electrical interference (e.g., 50/60Hz mains) can reduce noise.

For periodic interferences, use the Minimize Interference option. Small random pauses are inserted between stimulus presentations, minimizing the synchronization with electrical interference. These pauses do not influence latency times or in any other manner, change the behavior of ABRs.

Please refer to the Eclipse Additional Information for more information.

2. Use Insert Headphones
The recording below was carried out using reusable electrodes and headphones. Note the very large spikes before 1ms, especially on the curves at high intensities.

This is an electrical artifact caused by electrical coupling from the headphones to the input circuit when high sound stimuli intensities are used.

To solve this:

  • Always use insert earphones.
  • If using headphones they must be shielded. A shielded headset will still produce a small artefact using intensities above 90 dB SPL.
  • Start the recording window after the artifact.
 
July 2016

What is Bayesian Weighting?
Bayesian Weighting is a tool designed to assist the clinician when testing in less than optimal conditions. While giving sweeps with less noise a higher “score”, sweeps with more noise are not given the same level of importance in the overall recording. Each sweep is analysed and not simply accepted ot rejected as with traditional averaging but is given a unique signficance based on its level of noise. Baysian Weighting can be used in all typical ABR testing situations and will be effective when EEG levels vary during recording.

When and why to use Bayesian Weighting?
When

    • As Bayesian Weighting does not change the response of a waveform, you may use Bayesian in all typical ABR recording situations

Why

    • The optimum use of all data reduces test time.
    • More stable recordings, as residual noise will never suddenly rise (and a good waveform deteriorate) during recording, even if patient starts to be uneasy.
    • The difficulty of selecting the optimum rejection rate is reduced, as a softer rejection rate can be used without the noisier sweeps contaminating the more quite sweeps.

When is Bayesian Weighting less Relevant?
If the patient does not have a fluctuating EEG during the session:
Bayesian weights noisy sweeps less and quite sweeps more. In a situation where all sweeps are the same, they will be weighted equally. This is identical to normal averaging. Hence, there is no difference between recordings with and without Bayesian.

If a very tough rejection level is set: In this case, all noisy sweeps are simply rejected for both Bayesian and non-Bayesian recordings. Only the most quite sweeps are accepted, and you have a situation almost similar to above. With softer rejection criteria (e.g. 80μV) you would benefit from the contributions of the more noisy sweeps in your averaging thus arriving at your desired residual noise level in less time.

If you run long enough to get a low residual noise level
If two waveforms each have 40nV residual noise, then they will look equally clean. It does not matter whether you have used 1.000 or 10.000 sweeps to get there or what type of weighting is used. Weighting will simply get you there faster if the patient has fluctuating EEG during the session. It should be noted that two waveforms each with 40nV residual noise may exhibit minor variations in wave morphology due to e.g. the frequency distribution of the residual noise. This may differ with different test situations, and quite patients tend to provide residual noise with more high frequency content and less low frequency content, which may look nicer to the eye. So keeping the patient as relaxed as possible is still recommended.


References
Elberling, C. & Wahlgreen (1985). Estimation of auditory brainstem response, ABR, by means of Bayesian interference. Scand. Audiol (14) 89-96.

July 2016

Amplitude Ratio

Amplitude ratio is simply marked with the baseline, the summating potential and the action potential. A ratio between the BSL/SP and BSL/AP is calculated automatically by the system.

Area Ratio

PBSL=Baseline, SP= Summating Potential, AP=Action Potential, BLst=start of baseline, Blend=end of baseline, AP1=start of AP, AP2=end of AP

Area Ratio is marked by first marking the start of the baseline (BLst). The BL end will be marked automatically at the next point in the waveform where the amplitude crosses this baseline. If the waveform does not allow this, you can place the BL end manually. Now mark the SP and the AP1. (the beginning of the AP). Next mark the AP peak. Finally mark the AP2, which is where the AP ends and “changes direction”. A ratio is calculated automatically by the system.

Abnormal SP/AP amplitudes are exceeding a ratio of 0.53 as the critical value. Abnormal SP/AP area ratios are exceeding a ratio of 1.94 as the critical value (Devaiah et al., 2009).


References
Devaiah, A.K., Dawson, K.L., Ferraro, J.A., & Ator, G.A. (2003). Utility of area curve ratio electrocochleography in early meniere disease. Arch Otolaryngol Head Neck Surg, 129, 547-551.

July 2016

Prepare the equipment

  1. Turn on Titan by pressing the R or L button.
  2. Open the OtoAccess or Noah database and enter new patient details.
  3. Double click on the Titan Suite icon to launch the software and click on the ABRIS module tab.
  4. Select the desired test protocol from the dropdown list.
  5. Select the ear for testing.

Test environment 
The ideal test environment is a quiet room where lights and other electronic equipment are turned off.

Prepare the Infant 

Patient state

The infant should be sleeping or in quiet relaxed state. Sucking, blinking, crying or movement may affect testing.

Skin preparation

Typically, no skin preparation is required.
If the infant’s skin is oily, the electrode placement sites should be cleaned using alcohol wipes and/or skin preparation gel.
Use a conductive gel with the electrodes to improve impedances.

Place electrodes

Place surface electrodes using the desired montage (mastoid or nape).

Connect cables

Connect the cables from the PreAmplifier to the respective surface electrodes.

Check impedance
At the top of the screen, the impedance is indicated by the green/amber dots on the infant image.

When the dot is amber, this means the impedance is poor (> 40kΩ). In this instance , it may be necessary to clean the skin and/or use some conductive gel and replace the surface electrode.

NB. Testing is possible when impedances are poor. This may, however, affect test time and measurements

Place transducer/s
Place the probe or insert earphones in the infant’s ear/s or place the headset over the infant’s ears.

The probe light will turn green when a good seal is obtained.

Run test 
Click on START in the software, press the spacebar or press the preamplifier button.

Patient noise (EEG)
After starting the test, patient noise or EEG is displayed at the top of the screen (depending on setup).


The dark green bars should not reach the black bar


The EEG indicator should remain green

If the patient noise goes above the black line/EEG indicator turns red, try to calm the infant to reduce movement, crying, sucking etc.
If the infant appears calm and the patient noise/EEG is not ideal, stop the test and increase the rejection level using the arrow buttons.
If the patient noise/EEG signal is still not ideal, refer to the EEG troubleshooting section below.

Results

 PASS result
 REFER result

PASS –  when the result reaches 100% for the pass criteria, PASS is displayed in green above the measurement.
REFER –  when the result does not reach 100% for the pass criteria within the measurement time, REFER is displayed in amber above the measurement.
INCOMPLETE –  if the test is stopped before a PASS or REFER is generated by the system, INCOMPLETE is displayed above the measurement indicating that the full test was not completed.

EEG Troubleshooting 
When the patient noise/EEG signal is poor and the patient is calm, try the following:

  • Turn off (if possible) all electronic devices/sources, such as lights, computers, mobile phones etc.
  • Ensure that the Titan battery is not being charged (via the cradle) during testing.
  • If impedances were initially poor, clean the skin/use conductive gel and replace the electrodes.
November 2013

What is Neuro Latency Protocol?
The default Neuro Latency protocol is designed to evaluate the integrity of the neurologic system. The changes in response latency between the right and left ear at slow stimulation rates are recorded and compared. The Eclipse offers both markers and performs the calculation between the inter-peak Wave I, III & V latencies (between Left and Right). The purpose of the test is to look for retro cochlear pathology.

How does it Work?
The test is run like a traditional ABR. The clinician tests at a high intensity (ex. 80 or even 90dBHL) with a slow rate (i.e. 11.1Hz). The Wave I, III & V for the tracings is marked with the appropriate markers. After they are marked, interaural wave I, III & V and the intra-aural change is calculated.

An interaural difference of maximum 0.3ms is often used as critical value in clinical practice (Stürzebecher et al., 1985; Olsen et al., 1997). 


References
Stürzebecher, E. Kevanishvili Z., Webrs, M., Meyer, E., Schmidt, D. (1985). Interpeak intervals of auditory brainstem response, interaural differences in normal-hearing subjects and patients with sensorineural hearing loss. Scand Audiol (14)2 83.

Olsen, W.O., Pratt, T.L., Bauch C.D. (1997). Consistency in latency measurements and interpretation of ABR tracings.American Journal of Audiology, (6)57-62.

July 2016

Prepare the equipment 

  1. Turn on Titan by pressing the R or L button.
  2. Choose the test protocol from the list using the up & down arrow keys and then press Select.
  3. To use a different protocol than the one selected, press Protocol and then repeat step 2 above.
  4. Select the transducer (only if more than one connected to the preamplifier).
  5. Select the ear for testing.

Test environment 
The ideal test environment is a quiet room where lights and other electronic equipment are turned off.

Prepare the Infant 

Patient state

The infant should be sleeping or in quiet relaxed state. Sucking, blinking, crying or movement may affect testing.

Skin preparation

Typically, no skin preparation is required.
If the infant’s skin is oily, the electrode placement sites should be cleaned using alcohol wipes and/or skin preparation gel.
Use a conductive gel with the electrodes to improve impedances.

Place electrodes

Place surface electrodes using the desired montage (mastoid or nape).

Connect cables

Connect the cables from the PreAmplifier to the respective surface electrodes.

Check impedance
Impedances are indicated by the green/amber dots on the infant as well as in numerical format on screen.

When the dot is amber, this means the impedance is poor (> 40kΩ). In this instance, it may be necessary to clean the skin and replace the surface electrode.

NB. Testing is possible when impedances are poor. This may, however, affect test time and measurements.

Place transducer/s
Place the probe or insert earphones in the infant’s ear/s or place the headset over the infant’s ears.

The probe light will turn green when a good seal is obtained.

Run test
Press the START button on the Titan or press the preamplifier button.

Patient noise (EEG)
After starting the test, the patient noise/EEG bar is displayed at the top of the screen.

If the patient noise goes above the black line, try to calm the infant to reduce movement, crying, sucking etc.

If the infant appears calm and the patient noise is not ideal, stop the test and select a protocol with a higher rejection level (if available).

If the patient noise/EEG signal is still not ideal, refer to the EEG troubleshooting section below.

Results

PASS result
REFER result

PASS – when the result reaches 100% for the pass criteria, PASS is displayed in green above the measurement.
REFER – when the result does not reach 100% for the pass criteria within the measurement time, REFER is displayed in amber above the measurement.
INCOMPLETE – if the test is stopped before a PASS or REFER is generated by the system, INCOMPLETE is displayed above the measurement indicating that the full test was not completed.

EEG troubleshooting 
When the patient noise/EEG signal is poor and the patient is calm, try the following:

  • Turn off (if possible) all electronic devices/sources, such as lights, computers, mobile phones etc.
  • Ensure that the Titan battery is not being charged (via the cradle) during testing.
  • If impedances were initially poor, clean the skin/use conductive gel and replace the electrodes.
November 2013
  1. Prepare the infant’s skin before placing electrodes (if required). Clean oily skin using alcohol wipes/skin preparation gel. Use a small amount of conductive electrode gel to improve impedances.
    Forehead Right mastoid Left mastoid
  2. Place the surface electrodes (on the prepared skin).
    Forehead Right mastoid Left mastoid
  3. Attach the electrode cables to the surface electrodes.


    NB: Ensure the electrode cables are correctly attached to the preamplifier.
November 2013
  1. Prepare the infant’s skin before placing electrodes (if required). Clean oily skin using alcohol wipes/skin preparation gel. Use a small amount of conductive electrode gel to improve impedances.

  2. Place the surface electrodes (on the prepared skin).

  3. Place the surface electrodes (on the prepared skin).

    NB: Ensure the electrode cables are correctly attached to the preamplifier.

 
December 2013

OAE

There are a number of things to consider when conducting OAE testing in order to ensure valid and reliable results. Consideration of the factors below will ensure an optimal OAE test.

    1. Probe and cable configurations
      Ensure that the protocol that you select or create is valid for the test population and for the expected clinical outcome. Protocols generally differ between those used for Newborn Hearing Screening where a clinical outcome is based on a single test versus those used in a diagnostic follow up situation where the OAE result forms part of an overall test battery approach where many tests are analyzed to form a conclusion.

      Refer to the Titan Additional Information manual for more details about test parameter considerations when creating an OAE protocol. This document also highlights parameters to consider when creating a screening
      TEOAE protocol: Neonatal Hearing Screening and Assessment (2002). Transient Evoked Oto-Acoustic Emission (TEOAE) Testing in Babies. 


    2. Probe and cable configurations
      When performing OAE testing with Titan, it is important to use either the Long Clinical Extension cable with the shoulder box or the Preamplifier cable. As described in the manual, testing must not be conducted while the probe is directly connected to the Titan or directly connected to the Preamplifier cable. OAE tests should not be performed while holding the probe in the patient’s ear as this increases noise levels and the chance of incorrect delivery of the stimulus.


    3. Daily Probe Test
      Probe performance is crucial to OAE test results. It is common practice to conduct a probe test at the beginning of each day before starting to test on patients to ensure that the probe is functioning correctly.
        • Before conducting the probe test, ensure that the probe tip is clean and free of wax and/or debris.
        • Always conduct the probe test in a quiet test environment.
        • Only use the recommend cavity for testing. Using a different type of cavity may not detect probe faults.

      Refer to the TEOAE Probe Test Quick Guide for more information.

    4. Cleaning the probe tip
      It is important that the probe tip is clean and free of wax or other debris before conducting a test. Wax or debris in the probe tip can cause incorrect presentation of the stimulus or recording of the OAE. Refer to the manual or the Cleaning the Titan Probe Tip Quick Guide for more information.


    5. Probe placement
      A good probe placement will ensure a good test. Ensure that the correct size ear tip is selected so that the probe does not fall out of the ear during testing. Refer to the Selecting the Correct Ear Tip for Titan Quick Guide for more information.


    6. Test environment
      Ambient and physiological (patient) noise can affect the recording of an OAE response significantly. It is very important to conduct testing in a quiet environment and instruct the patient to be still and quiet during the entire test.


    7. Analyzing the result
      Depending on the type of test, screening vs diagnostic, the test analysis will differ. In screening, the protocol usually provides pass/refer labels for ease of understanding. In diagnostics, the stimulus, probe check, response waveform and OAE response graph along with SNR values are usually analyzed to form a conclusion of the test result.
May 2015
  1. Turn on Titan by pressing the R or L button.

  2. Select a tympanometry protocol (e.g., Tymp 226Hz) and record tympanometry measurements on the left and right ear.

  3. Save the tympanometry measurements to the handheld unit. Note: Tympanometry results do not need to be saved in order for the handheld unit to use the last recorded MEP data for pressurized OAE testing.

  4. Select a pressurized DPOAE protocol.

  5. Ensure the correct test ear is selected, so that the correct MEP is used from the tympanometry test.

  6. Press the start button and record the OAE. Change ears and repeat.

  7. Save results on the handheld unit.

Select a tymp protocol Record tympanograms Select a Pressurized DPOAE protocol Record & save DPOAE results

 

Note: Ensure that the Titan handheld unit is turned off between patients. The Titan handheld unit will always use the last recorded MEP measurements (right and left ear) for the pressurized OAE test.

November 2013

Prepare the equipment 

  1. Turn on Titan by pressing the R or L button.
  2. Open the OtoAccess or Noah database and enter new patient details.
  3. Double click on the Titan Suite icon to launch the software and click on the DPOAE module tab.
  4. Select the desired test protocol from the dropdown list.
  5. Select the ear for testing.

Test environment
The ideal test environment is a quiet room. High ambient background noise adversely affects OAE measurements.

Prepare the baby
The baby should be sleeping or in quiet relaxed state. Sucking, blinking, crying or movement may affect testing.

Place transducer
Place the probe in the ear –  the light will turn green when a good seal is obtained.

Run test
Click on START in the software, press the spacebar or press the shoulder box button.

Results

PASS result
REFER result

PASS –  when the criteria for a pass are reached, PASS is displayed in green above the measurement.
REFER –  when the criteria for a pass are not reached within the measurement time, REFER is displayed in amber above the measurement.
INCOMPLETE –  if the test is stopped before a PASS or REFER is generated by the system, INCOMPLETE is displayed above the measurement indicating that the full test was not completed.

November 2013

Prepare the equipment

  1. Turn on Titan by pressing the R or L button.
  2. Choose the test protocol from the list using the up & down arrow keys and then press Select .
  3. To use a different protocol than the one selected, press Protocol  and then repeat step 2 above.
  4. Select the ear for testing.

Test environment
The ideal test environment is a quiet room. High ambient background noise adversely affects OAE measurements.

Prepare the baby
The baby should be sleeping or in quiet relaxed state. Sucking, blinking, crying or movement may affect testing.

Place transducer
Place the probe in the ear –  the light will turn green when a good seal is obtained.

Run test
Press the START button on the Titan or press the shoulder box button.

Results

PASS result
REFER result

PASS –  when the criteria for a pass are reached, PASS is displayed in green above the measurement.
REFER –  when the criteria for a pass are not reached within the measurement time, REFER is displayed in amber above the measurement.
INCOMPLETE –  if the test is stopped before a PASS or REFER is generated by the system, INCOMPLETE is displayed above the measurement indicating that the full test was not completed.

November 2013
  1. Turn on Titan by pressing the R or L button.

  2. Select a tympanometry protocol (e.g., Tymp 226Hz) and record tympanometry measurements on the left and right ear.

  3. Save the tympanometry measurements to the handheld unit. Note: Tympanometry results do not need to be saved in order for the handheld unit to use the last recorded MEP data for pressurized OAE testing.

  4. Select a pressurized TEOAE protocol.

  5. Ensure the correct test ear is selected so that the correct MEP is used from the tympanometry test.

  6. Press the start button and record the OAE. Change ears and repeat.

  7. Save results on the handheld unit. 

Select a tymp protocol Record tympanograms Select a Pressurized TEOAE protocol Record & save TEOAE results

Note: Ensure that the Titan handheld unit is turned off between patients. The Titan handheld unit will always use the last recorded MEP measurements (right and left ear) for the pressurized OAE test.

November 2013

Prepare the equipment 

  1. Turn on Titan by pressing the R or L button.
  2. Choose the test protocol from the list using the up & down arrow keys and then press Select .
  3. To use a different protocol than the one selected, press Protocol  and then repeat step 2 above.
  4. Select the ear for testing

Test environment 
The ideal test environment is a quiet room. High ambient background noise adversely affects OAE measurements.

Prepare the baby
The baby should be sleeping or in quiet relaxed state. Sucking, blinking, crying or movement may affect testing.

Place transducer
Place the probe in the ear –  the light will turn green when a good seal is obtained.

Run test
Press the START button on the Titan or press the shoulder box button.

Results

PASS result
REFER result

PASS –  when the criteria for a pass are reached, PASS is displayed in green above the measurement.
REFER –  when the criteria for a pass are not reached within the measurement time, REFER is displayed in amber above the measurement.
INCOMPLETE –  if the test is stopped before a PASS or REFER is generated by the system, INCOMPLETE is displayed above the measurement indicating that the full test was not completed.

November 2013

Prepare the equipment 

  1. Turn on Titan by pressing the R or L button.
  2. Open the OtoAccess or Noah database and enter new patient details.
  3. Double click on the Titan Suite icon to launch the software and click on the TEOAE module tab.
  4. Select the desired test protocol from the dropdown list.
  5. Select the ear for testing.

Test environment
The ideal test environment is a quiet room. High ambient background noise adversely affects OAE measurements.

Prepare the baby
The baby should be sleeping or in quiet relaxed state. Sucking, blinking, crying or movement may affect testing.

Place transducer 
Place the probe in the ear –  the light will turn green when a good seal is obtained.

Run test
Click on START in the software, press the spacebar or press the shoulder box button.

Results

PASS result
REFER result

PASS –  when the criteria for a pass are reached, PASS is displayed in green above the measurement.
REFER –  when the criteria for a pass are not reached within the measurement time, REFER is displayed in amber above the measurement.
INCOMPLETE –  if the test is stopped before a PASS or REFER is generated by the system, INCOMPLETE is displayed above the measurement indicating that the full test was not completed.

November 2013

Tympanometry

Description
The acoustic reflex is the contraction of the stapedius muscle elicited by the presentation of an acoustically loud sound. When either ear is presented with a loud sound, the stapedius muscles on both sides contract. Contraction of the stapedius muscle tilts the anterior stapes away from the oval window and stiffens the ossicular chain. This results in increased impedance which is measured as a small decrease in compliance by an ear canal probe.
The stapedius muscle is innervated by the seventh cranial (facial) nerve (CNVII). Therefore, in the presence of CNVII paralysis, the stapedius muscle is likely to be affected.

Why perform the reflex measurements?
Acoustic reflex results make a major contribution to differential diagnosis and should be part of every basic audiological evaluation. They can provide/confirm information about the type (conductive, sensory, neural) and degree of hearing loss.

An acoustic reflex will most likely be elicited if all of the following conditions are met:

  1. Normal middle ear function
  2. Loud enough stimulus to elicit the response 
  3. No abnormal adaptation to stimulus

However, about 5% of the adult population have absent acoustic reflexes.

  • The pure tone intensity range to elicit an acoustic reflex is 70 to 100dBHL (median = 85 dBHL)
  • Ipsilateral ARTs in patients with normal hearing are usually 70-80dB above their pure tone thresholds, and about 5dB greater for their contralateral threshold (i.e., if pure tone thresholds were at 10dBHL, you would expect ipsilateral ARTs between 80 – 90dBHL and contralateral ARTs between 85-95dBHL as an approximation)

Contra-indicators for reflex testing

  • Tinnitus
  • Outer ear infection
  • Severe recruitment
  • Hyperacusis

How to setup the reflex protocol

  • Ipsi- and contra lateral pathway
    A protocol can be created to measure at either the ipsilateral pathway, contralateral pathway or both. Ipsilateral means “same side”, and contra means “opposite side”. The reflexes are always indicated by the probe ear.
    Ipsilateral pathway: The ipsilateral pathway can best be explained as follows. The loud sound travels through the outer, middle and inner ear, then along the vestibulocochlear nerve (CNVIII) to the brainstem arriving at the cochlear nucleus. From here the signal travels to the superior olivary complex and to the CNVII nuclei. The signal is then sent down the CNVII causing contraction of the stapedius muscle.
    Contralateral pathway: In the contralateral reflex pathway, the loud sound travels through the outer, middle and inner ear, then along the CNVIII to the brainstem arriving at the cochlear nucleus. From here the signal travels to the other superior olivary complex and the other CNVII nuclei. The signal is then sent down the CNVII causing contraction of the stapedius muscle.
  • Which probe tone should I use?
    Generally a 226Hz probe tone is used unless neonates are being tested. In this case a high frequency probe tone is used (1000Hz).

  • Acoustic Reflex Threshold (ART)
    The ART is the lowest intensity of an acoustic stimulus that elicits an acoustic reflex result (a measureable change in acoustic immittance). A change or deflection criteria of 0.03 is usually taken as the minimum change required to confirm the presence of a reflex.

  • Test frequencies
    ART measurements are usually conducted at 500, 1000, 2000, 4000Hz. Results are variable at 4000Hz and many normal hearing young adults have elevated ARTs at this frequency. Therefore, results should be viewed with caution. Some clinicians prefer to use a Broadband Noise (BBN) as an alternate stimulus to 4000Hz. Generally, noise stimuli elicit reflexes at lower levels than pure tones do; approximately 20dB lower.

  • Intensity
    The intensity should start from 70-80dBHL up to 105dBHL in 5dB steps until an acoustic reflex threshold is obtained. Depending on the required outcome of testing (screening vs clinical) it is not recommended to go above 105dBHL unless you suspect a conductive loss.
    Note: Acoustic reflex testing can cause permanent hearing damage and tinnitus and while there are no standards for safe presentation levels, most of the literature recommends testing no higher than 105-110dBHL.

  • Positive or negative reflex display
    Reflexes will either be displayed positively and negatively, depending on your setup of it.

     
    A negatively  displayed reflex   A positively displayed reflex

Procedure

  1. Alert the client that they will hear some loud sounds in either ear. Ask them to sit still and quiet.
  2. Place the immittance probe (probe used for tympanometry) into the ear you want to test. Place the contralateral probe into the other ear.
  3. Perform tympanometry first. Acoustic reflexes should be measured with the ear canal pressure set to obtain maximum compliance in the presence of the 226Hz probe tone (i.e., after tympanometry).
  4. Press Start.
    The measure will then run a reflex growth and stop automatically when a reflex is present with the defined threshold criteria.
    If the tone is loud enough and a contraction of the stapedius muscle occurs, the immittance probe will record that an acoustic reflex is present.
  5. The presence of a reflex is automatically confirmed by running the measure twice at the same intensity to confirm that the found threshold is reproducible. Alternatively, the measure can be repeated manually 5dB above the ART obtained to ensure it is a true ART.

 Reasons for repeating reflex measurements
If any of the following occur during testing, it is wise to retest to confirm your results are true:

  • Client swallows, talks, laughs, coughs etc. during the test.
  • You get an odd result that does not look correct or does not match audiogram findings. When in doubt, repeat the test to check your results are repeatable.
  • Collapsed canals can lead to false results, particularly if a headphone is used on the contralateral ear. Recheck results if they look suspicious or do not fit with the other test battery of results.

Interpretation of acoustic reflexes
The reflexes are indicated by the probe ear, so when obtaining the reflexes for the right ear, the probe is placed in the right ear and the contra headphone is placed on the left ear.

When obtaining reflexes for the left ear, the probe is placed in the left ear with the contra headphone placed on the right ear.

What characteristics am I looking for in my results?

  • the presence or absence of the stapedial reflex
  • an acoustic reflex threshold
  • acoustic reflex decay or adaptation (if tested)

The following is an example of what a reflex should look like. Here a deflection value is shown when a reflex is present. However, detection is based on the measurement matching an algorithm. It is therefore important for the clinician to look at the morphology of the reflex in conjunction with your testing situation (client talking, swallowing) and decide if the reflex is in fact a “true” reflex and not an artifact.

A reflex should show a downward deflection from 0.00 ml, which is time-locked to the stimulus presentation. It will then hold the change in compliance before offsetting back to 0.00 ml.

You will note in the example below that the reflex goes into the negative part of the graph before moving to the positive deflection point of 0.05ml. This type of response is called biphasic and can occur at the onset or both onset and offset of the reflex. The abnormal pattern of a biphasic response at both onset and offset is associated with otosclerosis, particularly in its early stages.

Examples of reflexes

Examples of non-reflexes

Why are these images not reflexes? In all but one example (highlighted green), the system has detected that these are not reflexes. In most of these examples, the client has either moved, swallowed or spoken during the test which has created an artifact.
In the first example, while it may appear to be a reflex, it has not been accepted as one because it has not met the deflection criteria as set by the instrument.
In the fourth (green highlighted) example, the system has detected this as a reflex, but in fact it is an artifact. You tell by looking at the shape that it does not match the pattern of a reflex. In this instance, you should repeat the test at that frequency to confirm the true ART.

Acoustic reflex patterns
Below are nine examples of reflex patterns you may come across during testing. However, you should be aware that these are not the results or patterns that you will see every time you test and real life clinical interpretations are much more complex. Different authors publish patterns or record results in different ways and therefore these tables below are a guide only.
Note that reflexes at 4000Hz may or may not be present due to variability at this frequency (discussed earlier). You may wish to use a BBN as an alternative to testing at 4000Hz.

Normal hearing and middle ear function
Generally for clients with normal hearing and normal middle ear function, both ipsilateral and contralateral reflexes will be present at all frequencies.

Example 1: Normal hearing/middle ear function

  Freq .5kHz 1kHz 2kHz 4kHz
Probe R Stim R (ispi) 85 85 85 85
Stim L (contra) 90 90 90 90
Probe L Stim L (ispi) 80 80 80 80
Stim R (contra) 85 85 85 85

Conductive hearing loss
Acoustic reflexes will be absent when a probe is placed in an ear with a middle ear disorder. This is due to the fact that middle ear disorders typically prevent the probe from measuring a change in compliance when the stapedius muscle contracts. Reflexes will therefore be absent even in the case of a mild conductive hearing loss. In the presence of a Type C tympanogram, depending on the degree of negative pressure in the middle ear, reflexes can be either present or absent.
If acoustic reflexes are present in the probe ear, it is unlikely that a conductive hearing loss exists, except in the rare case of Superior Semicircular Canal Dehiscence (SSCD).

Example 2: Normal hearing in the right ear & a mild conductive loss in the left ear

. Freq .5kHz 1kHz 2kHz 4kHz
Probe R Stim R (ispi) 85 85 85 85
Stim L (contra) 100 100 100 105
Probe L Stim L (ispi) X X X X
Stim R (contra) X X X X

In this example, the raised left contralateral reflex thresholds (probe right, stimulus left) are due to the additional SPL needed to overcome the mild loss in the L ear. The mild middle ear pathology may affect signals travelling through the left ear or being measured in the left ear. They will either be absent or raised.

Example 3: Normal hearing in the right ear & a moderate conductive loss in the left ear

  Freq .5kHz 1kHz 2kHz 4kHz
Probe R Stim R (ispi) 85 85 85 85
Stim L (contra) X X X X
Probe L Stim L (ispi) X X X X
Stim R (contra) X X X X

In this example, because of the moderate loss in the left ear, the stimulus (even at max levels) was not loud enough to elicit the stapedius reflex in the left contralateral recording (probe right, stimulus left).

Cochlear hearing loss
In ears with a cochlear hearing loss, it is possible for the acoustic reflex to be elicited at sensation levels (SL) of less than 60dB. The SL is the difference between the ART and the hearing threshold. For example, if the hearing threshold at 1kHz is 50dBHL and the ART is 90dBHL, the sensation level is 40dBSL.
When the SL is less than 60dB, a positive Metz test is indicated. This indicates a cochlear site of lesion (sensorineural loss) due to the loudness recruitment phenomenon.

Example 4: A mild to moderate cochlear loss in both left & right ears

  Freq .5kHz 1kHz 2kHz 4kHz
Probe R Stim R (ispi) 85 80 80 100
Stim L (contra) 85 85 90 X
Probe L Stim L (ispi) 85 90 85 100
Stim R (contra) 90 80 85 X

In this example, note that the ARTs occur at about normal levels. This is because the acoustic reflex threshold in an ear with a cochlear loss may resemble the results of a normal ear when the air conduction thresholds are below about 50dBHL. As the hearing threshold increases above this level, the chance of recording a raised or absent acoustic reflex increases.

Example 5: Severe to profound cochlear loss in left ear, normal hearing in the right ear

  Freq .5kHz 1kHz 2kHz 4kHz
Probe R Stim R (ispi) 85 85 85 95
Stim L (contra) X X X X
Probe L Stim L (ispi) X X X X
Stim R (contra) 90 90 90 95

In this example, the stimulus (even at max levels) was not loud enough to elicit a stapedius reflex due to the severe/profound loss in the left ear. Therefore, whenever a stimulus is presented to the affected ear, reflexes will be absent/raised in both ipsilateral and contralateral recordings as shown above.

Retrocochlear hearing loss
ARTs in ears with retrocochlear (CNVII) pathology are usually elevated above what they would have been for normal hearing or a cochlear hearing loss. Often they are absent at maximum stimulus levels. Keep in mind that ART results should be analyzed in combination with the patient case history, audiogram, speech and tympanometry findings for differential diagnosis.

Some things to note:

  • Ears with retrocochlear pathology and normal hearing do not have reflexes 30% of the time
  • With a mild 30dB hearing loss, the likelihood of absent reflexes increases
  • The absence of reflexes at 0.5, 1 & 2kHz in the presence of normal/near normal hearing must be considered suspicious unless proven otherwise
  • The affected ear will show absent acoustic reflexes when a stimulus is presented to it in the case of CNVIII lesions

Example 6: Retrocochlear lesion in the left ear; normal hearing in both ears

  Freq .5kHz 1kHz 2kHz 4kHz
Probe R Stim R (ispi) 80 80 80 90
Stim L (contra) 105 110 X X
Probe L Stim L (ispi) 110 X X X
Stim R (contra) 85 80 85 95

In this example, note the raised/absent acoustic reflexes with presentation to the left ear.

Example 7: Retrocochlear/CNVIII lesion in the left ear; a mild hearing loss in the left ear & normal hearing in the right ear

  Freq .5kHz 1kHz 2kHz 4kHz
Probe R Stim R (ispi) 80 80 85 85
Stim L (contra) X X X X
Probe L Stim L (ispi) X X X X
Stim R (contra) 85 85 90 90

In this example, note the absent acoustic reflexes when sound is presented to the left ear.

Facial nerve/CNVII involvement
Acoustic reflexes are absent when measured on the affected side in the case of a facial nerve disorder (e.g., probe in the affected ear). This is because the stapedius muscle is innervated by the CNVII.
Often, CNVII disorders are easily recognizable (e.g., facial paralysis in the case of Bell’s Palsy) and measurement of the acoustic reflex is used as a tool to monitor the recovery process in such patients.

Example 8: Facial nerve/CNVII lesion in the left ear due to Bell’s Palsy; normal hearing in both ears

  Freq .5kHz 1kHz 2kHz 4kHz
Probe R Stim R (ispi) 80 80 85 85
Stim L (contra) 85 85 85 90
Probe L Stim L (ispi) X X X X
Stim R (contra) X X X X

In this example, note that the acoustic reflexes are absent when the probe is coupled to the affected (left) ear. Also, you will recognize this is a similar pattern of results for a CNVIII lesion.

Inter-axial brainstem lesion

  • Very rare. About 1 in 10 million
  • Acoustic reflexes are normal ipsilaterally and absent contralaterally. The left and right pathways are disrupted by a lesion involving the auditory fibers.

Example 9: Intra-axial brainstem lesion; normal hearing in both ears

  Freq .5kHz 1kHz 2kHz 4kHz
Probe R Stim R (ispi) 80 80 85 85
Stim L (contra) X X X X
Probe L Stim L (ispi) 85 80 80 85
Stim R (contra) X X X X

 

Reflex Decay

Reflex decay testing can be useful in detecting/confirming retrocochlear pathology in patients. Generally patients will present with typical retrocochlear indicators (unilateral tinnitus, asymmetrical hearing loss, dizziness/vertigo) and you will have enough information to warrant a referral to an ENT specialist without needing to do this test. This test may be useful though when the audiogram and case history are normal, but reflex results show a retrocochlear pattern.

An acoustic reflex decay test measures whether a reflex contraction is maintained or weakens during continuous stimulation (usually 10 seconds). Testing is usually conducted at 500Hz and 1000Hz, but not above these frequencies as even normal ears can show decay at higher frequencies.
The test is performed by presenting a continuous stimulus 10dB above the ART for that frequency for a period of 10 seconds. Either the magnitude of the reflex response will stay the same or decrease over the 10 second period. What you are looking for is whether or not the response decays to half its original magnitude. Therefore, if the reflex response decreases to 50% of its original magnitude within the 10 seconds of testing, the test would be positive for reflex decay.

In the figure above (taken from Gefland, 2001), the acoustic reflex decay is considered negative if the reflex response does not decrease (example a) or if it decreases by less than half of its original magnitude (example b). Reflex decay is positive if the magnitude falls by 50% or more (as in example c).

Procedure

  1. Perform tympanometry and reflex measurements first.
  2. Take the acoustic reflex threshold at 500Hz or 1000Hz in the ear you want to test and add 10dB.
    This is the stimulus level you will use for testing (e.g., if the reflex threshold was 80dB at 1000Hz, you would test at 90dB at 1000Hz). The intensity is set automatically 10dB above the found reflex threshold.
  3. Make sure you still have a good seal between the probe and the ear and then press start to run the test.
    Note: If the reflex decay test is positive, you should check that it was not due to an improper seal, which might produce an artifact similar to a decaying curve.

Interpretation of reflex decay
Look at the recorded measurement. Typically you will see a result similar to the example below.
The decay value is the percentage difference of the two reflex deflection values taken half a second after the stimulus started and half a second before the stimulus stopped.

Example 1. In this example, the reflex decay test is negative as the response did not decay by more than 50% (drop below green dotted line), during the 10 second test interval. The blue reflex line would have had to drop below the green dotted line for positive reflex decay to be measured.

Example 2. This example shows a positive reflex decay measurement. The reflex has decayed by more than 50% (indicated by the green dotted line) during the 10 seconds test interval.


References
Bess, F.H., & Humes, L.E. (2003). Audiology: The Fundamentals (3rd ed.). Baltimore: Lippincott Williams & Wilkins.

Campbell, K.C., & Mullin, G. (2006). Impedance audiometry. Retrieved October 2, 2009.

Emmanuel, C. D. (2009). Acoustic reflex threshold (ART) patterns: An interpretation guide for students and supervisors. Retrieved October 2, 2009.

Fowler, C. G., & Shanks, J. E. (2002). Tympanometry. In J. Katz (Ed.), Handbook of clinical audiology (5th ed.). (pp. 175 – 204). Baltimore: Lippincott Williams & Wilkins.

Gefland, S.A. (2001). Essentials of audiology (2nd ed.). New York: Thieme Medical Publishers, Inc.

Margolis, R. H., & Hunter, L. L. (2000). Acoustic Immittance Measurements. In R. J. Roeser, M. Valente & H. Hosford-Dunn (Ed.), Audiology diagnosis. (pp. 381 - 423). New York: Thieme Medical Publishers, Inc.

Srireddy, S. V., Ryan, C. E., & Niparko, J. K. (2003). Evaluation of the patient with hearing loss. In J. Niparko & L.
R. Lustig (Ed), Clinical neurotology: Diagnosing and managing disorders of hearing, balance and the facial nerve. (pp. 65 – 80). London: Martin Dunitz Publishing.

Zito, F., & Roberto, M. (1980). The acoustic reflex pattern studied by the averaging technique. Audiology, 19, 395-403.

February 2017

Description
Electrical Evoked Stapedial Reflex Thresholds (eSRT) can be a very useful objective measure for the upper stimulus levels during the programming of a cochlear implant (Brickley et al., 2005; Buckler et al., 2003). The measure is particular useful during the fitting of cochlear implants in pediatrics (Cowdrey & Dawson, 2003), but also during the fitting on adults in particular adults unable to provide reliable behavioral measures (Andrade KC et al., 2013, Wolfe & Kasulis, 2008).

Required Items

  • A PC controlled Titan with an eSRT license.

When using the Titan to obtain the eSRT levels, the cochlear implant is used as the stimulus source, while the Titan is used for monitoring. Titan monitors if there is any change as a function of time when a stimulus is presented through the cochlear implant.

eSRT protocol setup
Enter Menu –  Seup –  Protocol Setup and create a protocol pressing New. Add the eSRT test as a protocol by selecting and pressing Add . Press Settings  to modify the protocol created.

eSRT parameters

Set the probe tone frequency to 226 Hz, 678 Hz, 800 Hz, 1000 Hz.
Check the box to obtain an eSRT at the ambient pressure. If unchecked, the pressure will be obtained at peak pressure, if a peak pressure is present.
The more smoothing that is applied, the less noisy/detailed the trace will be. The smoothing level can be set from 0-4, with 0 being no smoothing applied and 4 being maximum smoothing applied.

Display

Set the display of the reflexes to positive to have a positive deflection and negative to have a negative deflection of the reflexes.
This setting adds a threshold line to the graph, so it is possible to see when a threshold is present, e.g. by setting it for 0.05 ml.

Once the protocol is modified, press OK to save the changes to the protocol.

eSRT Test Screen

1 Protocol 

Select an eSRT protocol.

2 Probe tone

226Hz, 678 Hz, 800 Hz, 1000 Hz.

3 Probe status

Indicates probe status (in ear, out of ear, leaking, blocked).

4 Target pressure

Indicates how far the pressure is from target pressure.

5 Tests in protocol

Lists the tests that is part of the protocol, a checkmark at the right indicates the test is included, a checkmark at the left indicates data is obtained for the test.

6 Start/Stop

Start and stop the measurement. In case of drifting, Stop and Start the measure to reset the baseline.

7 Time scale

 The time scale is continuous. Use the slider to move back and forth on the time scale.

8 Time scale

Press the end of the time scale to go back to the point in time of the running measurement.

9 Threshold indication

The dashed line indicates the setting of the reflex threshold level, which is used to see when a reflex is present.

10 Marker

Use the marker (M) to indicate when a reflex is present. This is done by clicking with the mouse in top of the reflex. As default the marker will indicate Mnumber  (time).

11 Marker

Edit the name of the marker to help you identify which electrode it is from.
Press the trash bin to delete a marker.
By pressing the marker in the table the view of the graph with go to the point in time of the marker to see the reflex.

12 Save and review session

Press Save or Save & Exit to save the session. Review a saved session from the session list.

eSRT Procedure

  1. Open the Titan Suite so it runs in parallel with your cochlear implant fitting software.
  2. It is recommended that tympanometry is performed prior to measuring the eSRT to ensure that the condition of the outer and middle ear is normal. Normal tympanograms are often a requirement for being able to measure reflexes in the first place.
  3. Select the eSRT protocol you have created in the list of tests.
  4. Instruct the patient that they do not have to say or do anything during the test, they just have to sit still. However, they should let you know if they at any time feel uncomfortable with the stimulus being presented through the cochlear implant.
  5. Place the probe in the ear and ensure you get a tight seal. A good seal is important to avoid that the probe falls out of the ear during the measure.
    It is recommended to place the probe in the ear contralateral to the implant (Wolfe & Schafer, 2015).
    If there are any contraindications that the contralateral ear cannot be used for obtaining the eSRT, the reflex can be obtained ipsilaterally.
  6. Press Start .
  7. The Titan will monitor the changes as a function of time.
    Present the stimulus through the cochlear implant, one electrode at a time, and observe if a change occurs. It is recommended to present the stimulus in an ascending manner and increase the stimulus from the cochlear implant is sufficiently intense to elicit a deflection (Kosaner et al., 2009).
    Use the threshold indication line to see if a reflex is present.
    When a reflex is present, it can be marked pressing the area of the reflex with the mouse, this will assign a marker to the given reflex.
  8. In case of drifting, Stop and Start the measure to reset the baseline. Please also ensure that the probe is placed properly in the ear. This can be monitored during the measurement using the Probe status and Target pressure .
  9. Follow the procedure of 8-9 until you have obtained the eSRT for as many channels as possible. Remaining channels can be set using interpolation.
  10. Press Save to save the measure. Note the markers cannot be edited once the measure has been saved.

References
Brickley, G., Boyd, P., Wyllie, F., O’Driscoll, M., Webster, D., & Nopp, P. (2005). Investigations into electrically evoked stapedius reflex measures and subjective loudness percepts in the MED-EL COMBI 40+ cochlear implant. Cochlear Implants International, 6(1), 31-42.

Buckler L., Dawson K, Overstreet E. (2003) Relationship between Electrical Stapedial Reflex Thresholds and HiRes Program Settings.

Wolfe J., Schafer EC. (2015) Programming Cochlear Implants, Plural Publishing Inc. 2nd Edition

Wolfe J., Kasulis H. (2008) Relationships among objective measures and speech perception in adult users of the HiResolution Bionic Ear. Cochlear Implants Int. 9(2), 70-81.

Andrade KC., Leal MC., Muniz LF., Menezes PL., Albuquerque KM., Carnaúba AT. (2013). The importance of electrically evoked stapedial reflex in cochlear implant. Braz J Otorhinolaryngol. 80(1):68-77.

Julie Kosaner, Ilona Anderson, Zerrin Turan, Martina Deible (2009), Use of ESRT in Fitting Children with Cochlear Implants, Int. Adv. Otol. 2009; 5:(1) 70-79.

February 2017

Audiometry

Description
The Stenger test is based on the auditory phenomenon “The Stenger Principle” and is used when a patient is suspected malingering a hearing loss. The Stenger Principle states that only the louder of two similar tones presented to both ears at the same time will be perceived.
Generally, it is recommended only to perform the Stenger test in cases of unilateral hearing losses or significant asymmetries (at least 20dB).

Required Items

  • Headphones or insert phones
  • A response button

Test Procedure

  1. Press and hold the Tests button and use the scroll wheel to select Stenger.
    The Stenger test is as default set to present tones in both channel 1 and 2 simultaneously when pressing the tone switch of channel 1.
  2. Typically, the instruction to the patient is not different than with normal audiometry. The patient should not be informed that stimuli are presented at both ears simultaneously.
  3. Use Channel 2 for presenting tones to the better ear and set the intensity level to 10 or 20dB above the threshold (the example above shows 20dB).
  4. Use channel 1 for presenting tones to the poorer ear and set the intensity level 10 or 20dB below the level of the poor ear (the example above shows 40dB).
  5. Press the tone switch to present the tone on both channels. Keep the intensity level of the better ear fixed and increase the intensity for the worse ear in 5dB steps.
    If the hearing loss in the worse ear is genuine, the patient will keep responding to the signal presented to the better ear (Negative Stenger). If the patient is simulating the hearing impairment, he will not respond to the stimuli, which shows that the tone presented in the poorer ear is better than what the individual indicates (Positive Stenger).

Test Procedure for Speech Stenger

  1. Choose settings for Stenger using the input and output for channel 1 and channel 2:
    Channel 1 output: Right
    Channel 1 input: Mic, CD, or Wave 
    Channel 2 output:Left
    Channel 2 input: Mic, CD, or Wave
    Select Man in Channel 1 and select Sim in Channel 2 so that the speech is presented simultaneously in both channels.
  2. Clarify the test procedure to the patient. Explain that he/she will now hear speech and the assignment is to repeat the presented words or numbers.
  3. Use channel 2 for presenting speech to the better ear and set the intensity level to 20dB above the threshold.
  4. Use channel 1 for the poorer ear and set the intensity level 20dB below the level of the good ear.
  5. Present the speech material to both ears simultaneously. Keep the intensity level of the better ear fixed and increase the intensity for the worse ear in 5dB steps. If the hearing loss in the worse ear is genuine, the patient will keep repeating correctly to the speech signal presented to the better ear (Negative Stenger). If the patient is feigning the hearing impairment, he will stop repeating correctly when the level of the worse ear exceeds the signal presented to the good ear (Positive Stenger). 
July 2017

Description
Most people acquiring hearing aids report trouble hearing speech, or more often trouble hearing speech in noise. Here speech testing becomes a strong test tool in the assessment of the problem the patient faces. Speech audiometry employs speech signals and can be used to examine the processing ability and if it is affected by disorders of the middle ear, cochlea, auditory nerve, brainstem pathway, and auditory centers of the cortex.

There is a variety of tests available with speech testing with the basic speech audiometry being an assessment of the reception, discrimination and recognition of speech. Reception refers to the level at which the patient can hear speech is present, discrimination refers to the level at which the patient can discriminate between words, while recognition refers to the level at which the patient can recognize and recall the word.

More advanced speech testing takes into account how speech is understood in the presence of noise, with various noise types such as white noise, speech noise, babble noise, or running speech as noise source and provide information about the signal-to-noise ratio (SNR) at which the patient can understand speech. Other components such as the placement of the speech signal in relation to the noise source and the tonal differences between the speech signal and the masking signal, is some of the things incorporated into more advance speech testing.

Speech Detection Threshold (SDT)
Speech detection threshold (SDT) refers to the level at which the patient can hear speech is present in 50% of the cases.
The speech detection threshold can be used as a cross-check of the air conduction audiometry and should closely agree with the PTA (Pure Tone Average). The PTA can be calculated in different ways but is usually the average of thresholds obtained at 500, 1000, and 2000 Hz. It is generally accepted that if the PTA and the SRT is within ± 6 dB of each other the accordance is good, if it is ±7 to 12 dB it is adequate, and if it is ±13 or more, it is poor.

Note: Speech detection threshold is sometimes referred to as speech reception threshold abbreviated - SRT, not to be confused with speech recognition threshold, abbreviated - SRT. For that matter the term speech detection threshold is used and abbreviated – SDT.

Speech Recognition Threshold (SRT)
The SRT examines at which level 50% of the speech material (usually numbers or spondaic words) is repeated correctly.
In addition, SRT gives an index of the hearing sensitivity of speech and helps determine the starting point for other supra-threshold measures such as WR (Word Recognition).

Word Recognition Score (WR)
WR is sometimes also referred to as SDS (Speech Discrimination Scores) and represents the number of words correctly repeated, expressed as a percentage of correct (discrimination score) or incorrect (discrimination loss). Pressing correct means the word is a 100% correct, while incorrect correspond with 0% correct.
The score can be obtained as a phoneme score that provides information about what phonemes the patient has difficulty hearing at a particular intensity level. This is helpful for counselling and rehabilitation purposes.

Correct / incorrect (discrimination score / discrimination loss)
In the suite. Correct: A mouse click on this button will store the word as correctly repeated. The left arrow key can also be used for storing as correct. Incorrect: A mouse click on this button will store the word as incorrectly repeated. The right arrow key can also be used to score as incorrect. Store: A mouse click on this button will store the speech threshold in the speech graph. A point can also be stored by pressing S.

On the standalone devices. Press incorrect on the keyboard to store the word as incorrect (0%) or press correct on the keyboard to store the word as correct (100%).

Phoneme score

When the speech material is indexed according to the number of phonemes in each word, the soft key numbers avialable for scoring will be active. 

e.g. for a word with two phonemes the soft keys 0,1 and 2 will become available for scoring. The upper the display in the suites, while the lower displays the buttons on the standalone audiometer.
When the word is scored with the use of phonemes, the number of correct phonemes will appear below the word.

The percentage will be calculated as the numbers of phonemes correct out of the total number of phonemes that has been presented up until the given word.

Thereby the storing can be done at any time during the scoring.

What is required

  • Headphones, insert phones, or free field speakers
  • A microphone, external sound player, or built-in wave files
  • Talkback Microphone and Talk forward microphonel

Test Procedure

Before performing speech audiometry you may wish to do the tone audiogram. This provides valuable predictive information useful in the speech testing, including information about when masking is needed during speech testing. For more information about masking please refer to the quick guide ‘Audiometric masking’.

  1. Press the Tests button and select the speech test.
  2. If needed, select the measurement type (e.g. WR1, WR2, SRT), type of measure (word, numbers, multi syllabic numbers and multi syllabic words), and list of words using the soft buttons.
  3. Select the intensity levels for channel 1. If masking is needed configure channel 2 also.
  4. Explain to the patient that he/she will now hear some words/numbers/sentences though the ear phones/free field speakers. Instruct the patient to repeat what is said even though it may be very soft. Patients may also be encouraged to guess if they are unsure about the word/number/sentence. If performing the speech test in noise do not forget to instruct the patient not to focus on the noise but on the speech.
  5. Press Start to start presenting the words, numbers or sentences.
  6. Based on the settings for speech, the response can be scored as Correct, Incorrect using the hardkeys or numbers of correct phonemes using the softkeys
  7. Click on Store to store the results.

Speech results

Table mode
The SRT/WR displayed as a table allows for measuring multiple SRTs using different test parameters, e.g. Transducer, Test Type, Intensity, Masking, and Aided together with the SRT or WR score.

Graph mode
When showing the SRT in graph mode the speech audiogram calculates the SRT value based on the norm curve (the distance in dB from the point where the norm curve crosses 50% to the point where the speech curve crosses 50%) like shown below. The result is then an expression of how much you need to turn up the level compared to normal in order for the patient to be able to repeat 50%.

Use the m-curve for multi syllabic words and the s-curve if using single syllabic words. The curves can be edited according to the normative data you wish to use in the speech settings.

Note that the norm curves change based on the speech material. You must therefore ensure that WR1, WR2 or WR3 is linked to single or multisyllabic words to show the SRT. Calculating the WR SRT is only available when using the suite.

Speech setup
When running the speech test using wavefiles, the tester can decide to present manually, continuously or timeout for the speech setup.

Manual mode allows the tester to manually press the Tone Switch/Enter button to present the word and then score it as Incorrect of Correct before moving on to the next word.

In Continuous mode, the next word will automatically be presented after scoring incorrect or correct. In the Time Out mode, the word played will be scored as either correct or incorrect if no scoring is entered within 1 to 5 seconds.

Speech in Noise
Problems understanding speech in noise is a common complaint from people with hearing loss. Having the ability to test the patient with speech in noise provides useful information about the impact of the hearing loss on the patient’s ability to communicate. It also provides information about whether the patient is actually getting the expected benefit from the hearing aids when communicating in noisy environments.

Testing the patient in a speech in noise setup can be done using a free field setup either by presenting the speech signal and noise signal from the same speaker or alternatively, separating the speech signal and noise signal by presenting the signal from two different speakers. It can be done by presenting the signal and noise to the same ear on the AC40 or by selecting the test speech in noise on the AD629.

Binaural speech
If the intention is to present the speech signal to both ears at the same time this is done by selecting the same output for both channels on the AC40. On the AD629 the binaural speech is selected by choosing the test Speech - Ch2on. Note this is only available with the AD629 extended.


References
Stach, B.A (1998) Clinical Audiology: An introduction, Cengage Learning

November 2016

Description
Difficulty with hearing in background noise is a common complaint among hearing aid users. Therefore, the measurement of SNR loss (signal-to-noise ratio loss) is important because a person’s ability to understand speech in noise cannot be reliably predicted from the pure tone audiogram. The QuickSIN test was developed to provide a quick estimate of SNR loss. A list of six sentences with five key words per sentence is presented in four-talker babble noise. The sentences are presented at pre-recorded signal-to-noise ratios which decrease in 5-dB steps from 25 (very easy) to 0 (extremely difficult). The SNRs used are: 25, 20, 15, 10, 5 and 0, encompassing normal to severely impaired performance in noise.

The QuickSIN test was developed to

  • Provide a one-minute estimate of SNR loss
  • Provide a quick way for clinicians to quantify a patient’s ability to hear in noise
  • Determine if extended high frequency emphasis improves or degrades understanding of speech in noise
  • Assist professionals in choosing appropriate amplification and other assistive technologies
  • Demonstrate that hearing aids with directional microphones improve speech intelligibility in noise
  • Provide a large number of equivalent test lists for use in clinical and research work
  • Provide information useful in counselling patients regarding realistic expectations

Required Items

  • Headphones, insert phones, or free field speaker 
  • Standalone AC40/AD629/AA222, or in hybrid mode using Diagnostic Suite

Test procedure

  1. Press and hold the Tests button and use the black scroll wheel to select QuickSIN. The audiometer will automatically default to “wavefile”.
  2. Press and hold to select the desired wavefile, e.g. List 2. The first few lists in the list can be used for practice, so the user will familiarize with the test.
  3. Patient Instructions: “Imagine that you are at a party. There will be a woman talking and several other talkers in the background. The woman’s voice is easy to hear at first, because her voice is louder than the others. Repeat each sentence the woman says. The background talkers will gradually become louder, making it difficult to understand the woman’s voice, but please guess and repeat as much of each sentence as possible.Note: It may help to stress to the client to repeat what they have heard, even if they have only heard one word from the sentence as this may improve their score.
  4. Presentation level: You may choose your own preferred test level (Recommendation: 70dB HL level for a client with a pure tone average of 45dB or below. For pure tone average above 50dB HL, we recommend a level judged to be loud, but not discomforting for your client).
  5. Press to begin the test. 
  6. QuickSIN scoring: In each list there are 6 sentences, and in each sentence there will be 5 keywords highlighted in bold. You must score the client on how many of these key words the client correctly repeats back to you. Please score using the scoring from 0 through 5 using the soft buttons. Once a sentence is scored, the next sentence will be presented automatically.
  7. QuickSIN score: Once all 6 sentences have been scored. The SNR Loss is the score used to quantify the client’s difficulties and used to report the loss in dB. This score can be used to categorise the client’s degree of SNR Loss.
  8. Save the QuickSIN test by clicking the Save Session button.
  9. Averaging several QuickSIN lists (only lists 1-12 at the same intensity level) will improve the reliability of the results. This will be particularly useful for comparing two conditions i.e. Aided vs. Unaided or before and after hearing aid adjustments have been made.

Aided QuickSIN
It is possible to do an aided QuickSIN when using the audiometer via Diagnostic Suite, given the audiometer is free field calibrated. Making an Aided QuickSIN and an unaided QuickSIN is a useful tool to evaluate the benefit of a hearing aid treatment in a noisy environment.

Select Free Field as the transducer, this will activate the aided function. Click on the aided button, this will add an extra column to the QuickSIN scoring table allowing you to compare unaided and aided results.

QuickSIN Results
The SNR loss = 25.5 – Total, where the Total score is a sum of the score for each sentence (see example below). The SNR loss is then categorized based on the definition seen in the table in the test screen. Example: The total score is 22, which gives a SNR loss of 3.5. According to the definition the patient is having a Mild SNR loss. 


References
For more information, please refer to Etymotic Research’s QuickSINTM Speech-in-Noise Test manual, version 1.3.

June 2016

Description
In cases where you detect a symmetrical hearing loss, traditional audiometry without masking is usually sufficient. However, be aware that in cases of asymmetrical hearing loss, one cannot be certain that the intended ear is the one actually detecting the sound.

To prevent this phenomenon causing an erroneous measurement, masking noise can be used to occupy the good ear (non-test ear) while testing the other one (Stach 1998, Katz 2002 and British Society of Audiology 2004). Masking can be applied to air conduction, bone conduction and speech audiometry. The need to mask the better hearing ear is linked to the interaural attenuation, which equals the amount of attenuation the sound is exposed to on its way through the skull.

Even though the interaural attenuation is very individual and varies with frequency it can on average be estimated to a minimum of 40dB for supra-aural headphones and 50dB for inserts. Regarding bone conduction, the interaural attenuation is a minimum of 0dB which means that crossing over of the stimulus may occur at all times, and this is what one should assume.

Example
When measuring an audiogram on a patient with hearing within the normal range on one ear, but a moderate to severe hearing loss on the other, there is a potential risk of the good ear hearing the tone when trying to test the damaged ear. That is, the sound vibration may travel through the head and be heard by the opposite good ear when the vibrations of the signal are of sufficient

magnitude. Therefore, you are actually measuring the thresholds from the wrong ear. This could be the case in the example here and masking is needed in the right ear (better ear) while reassessing the left (poorer ear).

Masking is also needed to differentiate between sensorineural and conductive or mixed hearing losses. In the example, it is unknown if the loss of the left ear is sensorineural, conductive or a mixed hearing loss. The origin will be revealed by obtaining the bone conduction threshold for the left ear while occupying the right ear with masking.

Required Items

    • Headphones or insert phones
    • Bone oscillator

Test Procedure

  1. Perform air conduction audiometry unmasked for both ears.
  2. Perform bone conduction audiometry unmasked for both ears.
  3. Apply masking if needed:
    • In case there is an air-bone gap of 15dB or more, the bone conduction threshold must be reassessed while applying masking to the non -test ear.
    • If the difference between the air conduction threshold of the worse ear and the bone conduction threshold of the good ear exceeds IA of 40dB (50dB if using insert phones), masking will be needed for the air conduction audiometry of the worse ear.
  4. Select NB in channel 2.
  5. Select the ear to be masked (right or left) and choose the appropriate masking transducer(head phones or insert phones). This will activate the masking noise.
  6. Proceed to do a masked threshold search and press Store once a correct threshold has been obtained. The symbol will appear in the audiogram as masked.
    There are many ways of applying clinical masking. Which one to use is your decision. Regardless of the masking method, channel 2 is used to occupy the better ear.
  7. To display the masking level information on the screen, select Mask info.

In the example above, channel 2 should be set to Right (non-test ear) using the preferred masking stimulus (usually NB). Ensure that Rev is active to ensure that the masking noise is continuous. Channel 1 should be set to Left (test ear) using the preferred stimulus (usually Tone). The masking frequency will automatically change along with the tone frequency when masking is turned ON. You can set the masking and tone frequencies by using the Frequency Up Down buttons. While trying to establish the true threshold of the left ear, the right ear is now distracted with noise.

When storing a threshold while masking, the final masking level is stored in the masking table under the ear that is being tested. The terms ‘Effective masking’ in this situation refers to the fact that the narrow band noise level was loud enough to effectively mask a pure tone of the indicated level heard by the masked ear.

June 2016

Description
ABLB (Alternate Binaural Loudness Balancing) is a test to detect perceived loudness differences between the ears designed for people with unilateral hearing loss. It serves as a possible test for recruitment. The test is interpreted by assessing the loudness differences at high intensity levels. If the loudness perception is at the same intensity level for both ears complete recruitment has occurred in the hearing-impaired ear. Decruitment may occur in case of a retro cochlear disorder. In these cases, loudness in the impaired ear increases more slowly that for the normal hearing ear (Stack 1998).

The same tone is presented alternatively to both ears. The intensity is fixed in the impaired ear (20 dB above pure tone threshold). The task of the patient is to adjust the level of the better ear until the signal in the two ears is of equal intensity. Note however that the test may also be performed by fixing the intensity in the normal hearing ear and having the patient set the tone for the impaired ear.

Required Items

  • Headphones or insert phones
  • A response button

Test Procedure

  1. Clarify the test procedure to the patient. Explain that he/she will now hear tones in both ears, which will be presented alternatively in each ear. The patient should then inform the audiologist when the two tones sound equal in intensity/loudness.
  2. Press and hold the Tests button and use the scroll wheel on the audiometer to select the ABLB – Fowler.
  3. The Man Rev button on the audiometer is set to Rev. This will ensure continuous presentation of the tones, without having to stimulate manually.
  4. The ABLB is performed at frequencies where recruitment is assumed. Set the intensity level on the impaired ear to 20 dB above the pure tone threshold using channel 2.
  5. Present tones for both channels by holding in the tone switch for channel 1. Adjust the intensity level in the better ear until the perceived loudness is identical to the impaired ear using channel 1.
  6. Once the loudness is judged equally loud, press Store, and continue to the next intensity level.
  7. Measure at multiple intensities to get a laddergram that can be interpreted.
  8. To measure at a different frequency, use the Down Up buttons on the audiometer to change the frequency for testing at different frequencies.

ABLB Results
The ABLB results are interpreted based on the laddergram, which displays the difference between the intensities for the right and left ear. The good ear is used as reference and displays the normal dynamic range where no recruitment is present. The poorer ear will display a narrowed dynamic range which indicates a degree of recruitment. In the example above, the left ear is the reference ear relative to the right ear showing a narrowed dynamic range, indicating recruitment in the right ear. If the range of the poorer ear is the same as for the good ear there is no recruitment.


References
Stach A.A., 1998. Clinical Audiology: An Introduction. Cengage Learning

June 2016

Description
Hughson Westlake is an automatic pure tone test procedure. In this test method, the threshold of hearing is defined as 2 out of 3 (or 3 out of 5) correct responses during the ascending portion of the tone presentation. If the patient responds when the tone is ascending, the test will automatically decrease the level by 10 dB. The patient has to respond to the same intensity 2 out of 3 or 3 out of 5 times for the threshold to be recorded. Intensity increases will be in steps of 5 dB while the intensity decreases will be in steps of 10 dB.

Test Procedure

  1. Press and hold the Tests button and use the black scroll wheel to select Auto - Hughson Westlake.
  2. Instruct the patient that he will hear pulsed tones, which will vary in intensity and to press the button as soon as the tone is heard.
    Note If the response button is pressed after the patient heard the tones, the response will not be recorded. Therefore it is important to instruct the patient to press the response button as soon as the tone is heard.
  3. To familiarize the patient with the test, press the Famili and press Play.
  4. To start the test, deselect Famili, ensure to activate Trace and press Play.
  5. The Hughson-Westlake test will automatically store the threshold with 2 out of 3 (or 3 out of 5) ascending responses.
  6. All audiometric test frequencies will be measured automatically.
  7. The test will automatically switch to the other ear.
  8. To stop the test, press Stop.

To measure only one frequency, select the desired frequency and then press on the button Single.

To obtain a threshold including the high frequency range press the button High. Note The range is only available if it is selected in the SetupAuto settings.

Setup
SetupAuto settings allows for changing the threshold method 2 out of 3 or 3 out of 5. The frequencies included in the test is selected by ticking of the frequencies.

June 2016

Description
Masking Level Difference refers to the improvement in detecting a tone or speech in noise when the phase of the tone or the noise is reversed by 180 degrees. It aims to assess central auditory function and is specifically sensitive to brainstem lesions, but peripheral changes (like a hearing loss) may also affect the MLD.

The MLD is a low frequency phenomenon, related to the ability of the auditory system to perceive differences in timing of a sound reaching the two ears. This helps to localise low frequency sounds that reach the ears at different times due to the longer wave length.

The MLD is usually referred to as the difference of improvement in dB between a “homophasic” (in-phase) condition and an “antiphasic” (out of phase) condition. Homophasic means that both the signal and the noise are in phase with each other when reaching the two ears. Antiphasic means that either the signal or the noise (not both) is out of phase with each other when reaching the two ears.

The three test conditions for the MLD are:

  1. S0N0: Signal and Noise are IN PHASE when reaching the two ears (Homophasic condition). 

  2. SπN0: Signal is OUT OF PHASE, noise is IN PHASE when reaching the two ears (Antiphasic condition).

  3. S0Nπ: Signal is IN PHASE, noise is OUT OF PHASE when reaching the two ears (Antiphasic condition).

The MLD is measured by presenting a low frequency pulsed tone with simultaneous presentation of the corresponding narrow band noise, starting at an intensity of 60 or 65dB to both ears. The first condition should be to find the threshold for the homophasic condition (referred to as S0N0). The next step is to measure the antiphasic condition, either presenting the tone out of phase or the noise out of phase and the masked threshold is determined again. If the brainstem is functioning normally, there will be an improvement in the masked threshold from the homophasic condition to the antiphasic condition. The condition that will yield the greatest MLD is the SπN0 condition, that is, the condition where the signal is out of phase when reaching the two ears but the noise is still in phase.

Required Items

  • AC40 audiometer
  • Headphones or insert phones
  • A response button 

Test Procedure

  1. Press and hold the Tests button on the audiometer and use the scroll wheel on the audiometer to select MLD: Masking Level Difference.
  2. Before mounting the headphones on the patients, explain to them that they will now hear tones (identical to the ones from the air conduction audiometry) and noise through the headphones. Emphasize that they should only focus on the tones and press the response button whenever it is audible.
  3. Select the frequency that you would like to test; 250Hz or 500Hz is a good starting point.
  4. Select S0N0 and set the intensity level for both channels at 60dB.
  5. Ensure that the decibel steps are set to 2dB.
  6. S0N0: The signal will be presented to both ears in phase (S0N0). Narrow band noise is also presented at a fixed level.
    Make a masked threshold search. The threshold will typically be equal to the noise in the S0N0 condition.
  7. When you have established a threshold, click in the Store button.
  8. SπN0: Select the SπNo button, leaving the narrow band noise intensity level at 60dB. The pulsed tone detection should lower significantly.
  9. The difference between the S0N0 threshold and the SπN0 threshold will be the MLD.
  10. S0Nπ: If desired, you can also establish the threshold for the S0Nπ condition.
  11. Press  to end the test.

 MLD Result

Example
The masked threshold for the S0N0 condition is 60dB and we reverse the phase of the signal by 180 degrees the threshold for this phase reversed condition (SπN0) improves to 44dB. Then the masking level difference (MLD) from SoNo to SπN0 is 16dB.

Most research having been done on the MLD indicates that in general, if the MLD is less than 7dB, this will indicate a problem with the brainstem and binaural interaction. There will also be a decrease in the hearing MLD if there is a peripheral hearing loss or if the hearing aid is asymmetrical. A normal result for MLD is usually around 12dB (Brown & Musiek, 2013).


References
Brown, M., Musiek, F. (2013). The Fundamentals of MLD for Assessing Auditory Function. Hearing Journal

June 2016

The purpose of this document is to provide a Quick Guide for instructions on how to administer the Acceptable Noise Level (ANL) test with the AC440 Audiometry module in the Equinox 2.0, Affinity 2.0 and Callisto™.

What is the ANL test?
The ANL Test is a method of determining how much noise the patient is able to tolerate whilst listening to a target signal/speaker (Nabalek et al., 1991). It is used as a predictor for how well a patient will cope with amplification when receiving a hearing aid (Nabalek et al., 2006).

The ANL test is designed to be performed via loudspeaker as it is a free field test. However, it can be configured to perform monaurally via selection of headphones and routing the signal to the relevant ear-side. The Equinox and Affinity systems can perform the test binaurally via the R+L feature.

The ANL Test can use any of the materials you have already ripped into your Interacoustics Suite software.

When should I perform the ANL test?
The ANL test is typically performed before the patient is given any form of amplification as a rehabilitative action for their hearing loss.

Test Procedure

    1. Launch the Affinity 2.0/Callisto™ Suite from Noah or OtoAccess™.
    2. Click on the AUD tab on the upper right hand side of the screen. Ensure that your Audiometry has been performed ahead of advancing into the SIN test as this determines the start level for the test.
    3. Click on Menu, Tests and then select ANL

    4. Once in the ANL test screen, you will see that there are 4 different conditions which you can choose to measure.

      MCL High – This is the loudest comfortable level the patient can listen to without any competing noise
      MCL Low – This is the lowest comfortable level the patient can listen to without any competing noise
      MCL Real – This is the patient most comfortable level without any competing noise
      BNL – This is the actual ANL test where the MCL Real is presented and the competing noise is manipulated to find an ANL value

      It is not essential to perform MCL High and MCL Low for the ANL test, but these are also good indicators of the patients’ comfortable hearing range.

      Instructions for the patient will always be displayed at the bottom of the screen.

    5. MCL High
      Click on the MCL High Icon and click play. This will loop your speech material.
      Increase and decrease the stimulus intensity to match the patients loudest MCL.
      There will be no other change in the display to represent this, only the level in the MCL High icon box. 

    6. MCL Low
      Click on the MCL Low Icon and click play. This will loop your speech material.
      Increase and decrease the stimulus intensity to match the patients lowest MCL.

      The display will change within the icon but also a predicted MCL Real will be generated as a midpoint between the MCL High and MCL Low.

    7. MCL Real
      Click on the MCL Real Icon and click play. This will loop your speech material.
      If you have performed the MCL High and MCL low you should already have a predicted MCL value here. If not then increase/decrease the intensity to find a suitable level for the patients MCL.
      Again the display will not change, other than inside the icon for your test condition.

    8. BNL
      Click on the BNL Icon and click Play. This will loop the same speech material but also introduce the background masking noise.
      Increase/decrease Channel 2 in order to find a level of competing noise which the patient would be comfortable to listen to alongside their target material. Whilst doing this you will notice the display will change to reflect the patients ANL value and the prediction percentage of how well they will perform with amplification.

What does my ANL value mean?
On performing the ANL test you will obtain an ANL value (in dB) and a percentage. The percentage gives a likelihood of success with amplification (Nabalek et al., 2006) and the ANL value is the outcome of the following calculation:

ANL = MCL - BNL

For response categories the following outcome criteria was determined as an effect of the Nabalek et al. (2006) investigation into ANL outcomes in relation to amplification:

ANL Score 7 dB or less: These individuals have a great prognosis for regular use and acceptance of hearing aids; may not need as much follow-up counseling and guidance as the average patient.

ANL Score 8-12 dB: These are your more common patients and have a good (8) or bad (12) prognosis for regular use and acceptance of hearing aids. These patients may need more follow-up counseling and are excellent candidates for noise reduction technologies.

ANL Score 13 dB or more: These patients are “at risk” for reduced utilization of hearing aids and may need additional post-fitting counseling, guidance, and require noise reduction technologies.


References
Nabelek, A.K., Tucker, F.M., & Letowski, T.R. (1991). Toleration of background noises: Relationship with patterns of hearing aid use by elderly persons. Journal of Speech and Hearing Research, 34, 679-685.

Nabelek, A., Freyaldenhoven, M., Tampas, J., & Burchfield, S. (2006). Acceptable noise level as a predictor of hearing aid use. Journal of the American Academy of Audiology, 17(9), 626-639.

May 2017

The purpose of this document is to provide a quick guide and an overview on using the Callisto™ system to perform QuickSIN testing.

The QuickSIN test was developed to:

  • Provide a one-minute estimate of SNR loss
  • Provide a quick way for clinicians to quantify a patient’s ability to hear in noise
  • Determine if extended high frequency emphasis improves or degrades understanding of speech in noise
  • Assist professionals in choosing appropriate amplification and other assistive technologies
  • Demonstrate that hearing aids with directional microphones improve speech intelligibility in noise
  • Provide a large number of equivalent test lists for use in clinical and research work
  • Provide information useful in counseling patients regarding realistic expectations

QuickSIN for the AUD440 Module

  • To enable QuickSIN testing from your Audiometry Screen select: Menu →Test->QuickSIN
  • Transducer: QuickSIN can be performed using the headphones (right or left ear) and through the Callisto™ speaker. Please select Right, Left or FF1 (speaker) from the drop down list in Channel 1. (Please note: the Callisto™ speaker is not calibrated for free field testing, therefore the intensity should not be used for diagnostic reporting – the CallistoTM speaker can be used to compare Aided vs Unaided or demonstrate SNR loss testing at an uncalibrated level)
  • Presentation Level: You may choose your own preferred test level. (Recommendation: 70dB HL level for a client with a pure tone average of 45dB or below. For pure tone average above 50dB HL, we recommend a level judged to be loud, but not discomforting, for your client).
  • Patient Instructions: “Imagine that you are at a party. There will be a woman talking and several other talkers in the background.
  • The woman’s voice is easy to hear at first, because her voice is louder than the others. Repeat each sentence the woman says. The background talkers will gradually become louder, making it difficult to understand the woman’s voice, but please guess and repeat as much of each sentence as possible.” Note: It may help to stress to the client to repeat what they have heard, even if they have only heard one word from the sentence as this may improve their score.
  • QuickSIN Methodology: A list of six sentences with five key words per sentence is presented in four-talker babble noise. The sentences are presented at pre-recorded signal-to-noise ratios which decrease in 5-dB steps from 25 (very easy) to 0 (extremely difficult). The SNRs used are: 25, 20, 15,10, 5 and 0, encompassing normal to severely impaired performance in noise.
  1. There are up to 3 practice lists to help familiarise the test for the client, lists 1-12 are to be used for basic QuickSIN testing and they can be selected from the drop down menu highlighted below.

Press start to begin the first sentence on the selected list. The next sentence will automatically play once you have scored the previous sentence.

  • QuickSIN scoring: In each list there are 6 sentences, and in each sentence there will be 5 key words highlighted in bold. You must score the client on how many of these key words the client correctly repeats back to you. Please score using the scoring screen on the top-centre of the screen and the Callisto will automatically move on to the next sentence.
  • QuickSIN score: Once the last sentence has been scored using the numbers above, a total and SNR loss will be given. The SNR loss is the difference in the patient’s performance in noise compared to normal hearing persons’ performance in noise. The SNR Loss is the score used to quantify the client’s difficulties and used to report the loss in dB. This score can be used to categorise the client’s degree of SNR Loss and the expected improvements with directional mics can be seen in the graph below.
  1.  Averaging several QuickSIN lists (only lists 1-12 at the same intensity level) will improve the reliability of the results. This will be particularly useful for comparing two conditions i.e. Aided vs. Unaided or before and after hearing aid adjustments have been made.
  • We do not recommend you save the QuickSIN results in the Callisto AC440 as this will save as a blank audiogram in your Noah system. The results should be used to report in the client’s notes i.e. client has a 12.5 dB SNR Loss at 70dB HL in the right ear. If you would like to save the results in your Noah session please ensure the clients Audiogram is inputted in the ‘tone audiometry’ screen.

Additional QuickSIN features
Adding a fourth column to the SNR loss definitions table:

  1. Go to: Menu → Setup → AC440 → Main Setup → QuickSIN → Common
  2. and insert a checkmark in the “show fourth column” box
  3. Click on the pencil icon to enter text in the text box
  4. Click on the dropper icon to add colour to the text box

Aided QuickSIN is possible when selecting the free transducer 
To activate Aided QuickSIN:

  1. Select Free Field as the transducer; this will activate the "Aided" function. 
  2. Click on the Aided button; this will add an extra column on to the QuickSIN scoring table 
  3. Clinicians will then be able to compare the Unaided and Aided SNR scores. To view the scores in a graph view, click on the graph icon
  4. Results can also be shown on the patient Monitor
 
December 2013

Description
Békésy is an automatic method of measuring audiometric thresholds. It can be used for audiometric screening or in differentiation between the cause of the hearing loss e.g. non-organic hearing loss (Gelfand, 2009) or the origin of the damage in the ear (conductive, cochlear or retro cochlear) (James Jerger, 1962).

The patient being tested needs to hold down the response button when the tone is heard and release when the tone is no longer heard. When the response button is pressed, the intensity level of the frequency tested will automatically be reduced. When the response button is released, the intensity level will automatically increase. The patient’s response will be recorded as a trace on the Test Screen.

Required items

    • Headphones or insert phones
    • Patient response button

Test Procedure

    1. Press and hold the Test button and use the black scroll wheel to select Auto – Békésy.
    2. Instruct the patient that he will hear some tones, which will vary in loudness and that he must press the response button as long as the presented tone is heard and let go when the tone is not heard.
    3. The tone is obtained with a continuous tone. To obtain the tracing with the pulsed tone, press the Single Multi button and ensure that Multi is selected.
      Note the timing of the pulsed tone can be adjusted from the default setting by pressing and holding Setup, selecting Common and then reducing the Multi, pulse length slider.
    4. To familiarize the patient with the test, press the button under Famili and press Play.
    5. To start the test, deselect Famili and select the button under Trace and press Play.
    6. Traces should be obtained for the desired audiometric test frequencies.
    7. To use the Békésy with different traces, complete the measure with a continuous tone and obtain the second trace with a pulsed tone (see example below).

Békésy Results
When using the Békesy for clinical purposes, one threshold is obtained with a continuous tone and one with a pulsed tone. The results are interpreted based on the display of the continuous and pulsed tone.

Békésy Type 1: Continuous and pulsed tone overlapped (Cochlear disorder)
Békésy Type 2: Continuous tracing slightly worse than pulsed tone tracing (Cochlear disorder) Békésy Type 3: Continuous drops off the graph as a result of adaptation to the tone (Retro cochlear disorder)
Békésy Type 4: Continuous tracing is 20 dB lower that pulsed tone tracing (Retro cochlear disorder)
Békésy Type 5: Pulsed tone tracing below continuous tracing (feigning hearing loss)

Setup
Setup
Auto settings allows for changing the allowed deviation and number of reversals needed for a response to be stored.


References
Gelfand, S.A. (2009) Essentials of Audiology, Theime.

Jerger, J. (1962) Bekesy Audiometry, Hearing Tests in Otologic Diagnostics, ASHA May.

June 2016

Description
SISI is designed to test the ability to recognise 1dB increases in intensity during a series of bursts of pure tones presented 20dB above the pure tone threshold for the test frequency. It can be used to differentiate between cochlear and retro cochlear disorders, as a patient with a cochlear disorder will be able to perceive the increments of 1dB, whereas a patient with a retro cochlear disorder will not.

Required Items

  • Headphones or insert phones
  • A response button

Test procedure

  1. Press and hold the Tests button and select SISI: Short increment sensitivity index using the scroll wheel on the audiometer.
  2. Select Tone or Warble in channel 1. If cross hearing is suspected, masking should be presented in channel 2.
  3. Select the desired test frequency and set the input level 20dB above threshold using the scroll wheel on the audiometer.
  4. In the most common type of SISI test, the incremental steps are set to 1dB. By pressing and holding the function button AM, it is possible to change the increments. Prior to presenting the actual test of 1dB increments, a trial of 2 or 5dB steps can be employed to ensure that the patient understands the test procedure and what will be required. If you are uncertain about the responses from the patient, 0dB can be used.
  5. Explain to the patient that they will now hear a series of tones. If suddenly there is a change in the loudness of the presentation of the tone, the response button should be pushed.
  6. Start the test by pressing . The system will automatically count the number of reactions from the patient. Note that the system needs 20 presentations to calculate a SISI score.
  7. Repeat the test for all desired test frequencies.
  8. Press  to end the test.
  9. Save the SISI test by clicking Save Session.

SISI Results
The SISI test should be conducted at 20dB SL for all frequencies tested. If the patient does not manage to get a high score on the SISI test, this could be indicative of retro cochlear damage.

June 2016

Description
This is a test to help identify the adaptation of the auditory system (Carhart, 1957). It involves measuring the perceptual reduction in a continuous tone over time. This can indicate towards a cochlear or neural cause ofdeafness.
The test involves looking at the patient’s response to the onset of a supra-threshold sound and then their continuous response to this as it continues over time. For example, in Meniere’s disease this is detected correctly on onset but rapidly deteriorates due to dysfunctional hair cells (Carhart, 1957). A normal response should be maintained for a minute of stimulation. Should a patient not be able to maintain this, the stimulus intensity is increased until a minute is achieved. This is only increased up to a maximum 30dB suprathreshold.

Required Items

  • The AC40 hardware
  • Calibrated headphones or insert phones
  • Patient response button

Tone Procedure
The tone decay can be run on the AC40 as standalone or by using the AC40 with Diagnostic Suite.

  1. The patient’s audiometry is obtained.
  2. Press the Tests  button and select Tone decay  from the list of test by rotating the wheel.
  3. The patient is then instructed to continuously respond to the tone by pressing the response button if they hear the tone and not respond as the signal fades/is absent by letting go of the response button.
  4. Press Start.
    The test is administered with a pure tone presented at 5dB SL and then ascended in 5dB steps without interruption until the subject responds. As soon as the subject responds, the system will begin timing.
    If the tone is heard for a full one minute, the test is stopped.
    If the subject indicates that the patient no longer hears the tone before the minute criterion is reached, the intensity of tone is increased by 5dB without interrupting the tone, but the timing at the top of the screen is reset. The tone is continued to be raised in 5dB steps until an intensity is reached that allows the subject to perceive the tone for a full minute.
    The results are stored in the bottom of the test window for the given ear and frequency, showing the amount of decay occurring.
  5. As a time saving measure, Carhart (1957) suggested that the test should be terminated when the subject fails to respond 30dB above threshold.
June 2016

The purpose of this document is to provide a Quick Guide for instructions on how to administer the TEN test with the AC440 Audiometry module in the Equinox2, Affinity2 and CallistoTM. This Quick Guide is based on a white paper that was written for Interacoustics by Brian C.J. Moore (2009)

What is the TEN test?
The TEN(HL) test was developed to provide clinicians with a quick and easy way to identify cochlear dead regions. The test consists of measuring pure tone thresholds in a special masking noise, called the TEN (Threshold Equalizing Noise).

What is a dead region?
A dead cochlear region is defined as a region of the cochlea where there are no functioning inner hair cells and/or neurons. (Moore, 2001). When a pure-tone signal “falls” into a dead region, it can be heard by neighboring hair cells, if the intensity of the signal is loud enough. This is because the pure tone produces sufficient basilar-membrane vibrations in neighboring areas of the cochlea, where there are surviving IHCs and neurons. This phenomenon is defined as “Off Frequency Listening”. Clinically, this will present as a threshold on the traditional pure tone audiogram, but it may not be the real threshold. It is not possible to use traditional pure tone audiometry to determine if there is a dead region present; the TEN test was developed for this very purpose.

When to do the TEN test?
Characteristics that could indicate the presence of a dead region (from Moore, 2009):
 

  • Severe to profound hearing loss
  • Absolute threshold is at a specific (suspected) frequency is 70 dB HL or greater
  • Steeply sloping hearing loss
  • Complaints of distortion
  • Extremely poor speech discrimination

Criteria for diagnosing a dead region (Moore et al) :

A dead region at a particular frequency is indicated when:

A masked threshold is at least 10 dB or more above the level of the TEN
AND
Masked threshold is at least 10 dB above the non-masked threshold

 

Note: the TEN test is performed ipsilaterally, meaning that the tone and the noise are presented in the same ear. It can only be conducted with TDH39, DD45 and Insert earphones headphones

Setup:

  1. Launch the Affinity 2.0/Callisto™ suite from your patient management system, Noah or OtoAccess™.
  2. Ensure you are in the AUD module (click on the AUD tab on right hand side of the screen if not)
  3. Choose TEN1 test from the Protocols and sessions drop down menu
  4. Transducers: Select the desired transducer and ensure that the stimulus is directed to the same ear in channel 1 and channel 2 (see below). If testing the right ear, select Phone right for both channels (see below)
  5. Stimulus/Input: Tone for Channel 1 and TEN for channel 2 (see below)
  6. Set the masking to Rev to have a continuous masking signal. To stop the masking, click on Man or hover the mouse over the Stimuli button (see below)

  1. Set the intensity levels (Moore, 2009)
    • For frequencies where hearing loss up to 60 dB HL: set the TEN level to 70 dB.
    • For frequencies where hearing loss is 70 dB or more: set the TEN level 10 dB above the audiometric threshold at that frequency. For example, if the audiometric threshold is 75 dB HL, set the TEN level to 85 dB HL.
    • If the TEN is too loud, or if the maximum TEN level of 90 dB HL is reached, then set the TEN level equal to the audiometric threshold. This should still give a definitive result.
  2. Conduct a threshold search using the traditional method for air conduction
  3. Repeat for each frequency where a dead region is suspected

Positive TEN test

A dead region at a particular frequency is indicated when:

A masked threshold is at least 10 dB or more above the level of the TEN
AND
Masked threshold is at least 10 dB above the non-masked threshold

Clinical Value of TEN test
If dead regions are present, this may have important implications for fitting hearing aids and for predicting the likely benefit of hearing aids. When a patient has a dead region, there may be little or no benefit from hearing aid amplification for frequencies well inside the dead region (Moore 2009).

Identifying a cochlear dead region can:

  • Help counsel the patient and manage expectations regarding the potential benefit of hearing aids
  • Helps on choice of type of hearing aid
  • Can help determine if a patient would be a good candidate for cochlear implants
    • Patient might do better with an implant when there are extensive dead regions
    • Helps determine insertion depth

1TEN test requires an additional license

References 
Moore, B. C. J. (2001). "Dead regions in the cochlea: Diagnosis, perceptual consequences, and implications for the fitting of hearing aids," Trends Amplif. 5, 1–34.

Moore, B. C. J. (2009). “Audiometer Implementation of the TEN (HL) Test for Diagnosing Cochlear Dead Regions” . White Paper for Interacoustics.

December 2013

Description
High frequency audiometry (above 8 kHz) is performed using the same procedure as normal air conduction audiometry. High frequency audiometry is helpful when testing hearing impairments caused by ototoxicity, noise exposure, and acoustic traumas or in the assessment of patients with tinnitus. The frequency area is more susceptible to the effects of external factors such as medication and loud noises relative to the low and mid frequencies.

Required Items

  • A response button
  • High frequency audiometry headset (HDA300) and a high frequency license installed

    Note: High frequency audiometry is only available if the optional high frequency license is installed on the instrument. If the license is not installed or if the headset is not calibrated for high frequencies the HF phone button does not appear on the audiometer and the HF button and HFz button will be dimmed in Diagnostic Suite.

Test Procedure

  1. To perform HF Audiometry, select the Tone and HF Phone; this will activate the HF Audiometry function.
  2. Choose between HF and HFz; shows the full range of audiometric test frequencies, whereas HFz only shows the high frequency range  or  in Diagnostic Suite.
  3. Use the high frequency headset to perform a high frequency audiometry. The audiometry is performed in the same way as a normal air conduction audiometry would be performed.
 
June 2016

Description
The purpose of tone audiometry is to establish the hearing sensitivity at various frequencies for air conduction and bone conduction. The test can specify the air conduction and bone conduction loss and distinguish between abnormality in the conductive mechanism and sensor neural mechanism. Masking can be applied to both the air conduction and bone conduction threshold to establish pure tone thresholds.

Required Accessories

  • Headphones or insert phones
  • Bone Oscillator
  • A response button

Starting up the Tone Audiometry

  1. Turn on the Audiometer.
  2. The Audiometer stats up in the Tone Audiometry screen by default.
  3. Settings of view and default test procedure can be set temporary or permanent from Setup │Tone settings. By saving the user setting you created, the system will start up in your preferred protocol setting.
  4. The light indicators on the audiogram will indicate the transducer type, stimulus type, ear, etc.
  5. Use the Right wheel to control channel 1 and adjust the intensity level of the stimuli. 
    Use the Frequency Down/Up to change frequency.
    Use the Left wheel to control channel 2 to apply and adjust the masking level.
  6. Press Store to store a threshold.

For a more detailed description on how to use the stand-alone audiometer, please refer to the relevant Instructions for Use.


Tone audiometry in Diagnostic suite


Starting up the AC440 Module

  1. Launch the audiometer PC controlled from the Diagnostic Suite as stand-alone or from NOAH or OtoAccess™.
  2. Click on the AUD tab on the upper right hand side of the screen.
  3. Click on the  icon to launch the tone audiometry screen, if Tone audiometry is not the default screen.
  4. Select the desired Audiometry protocol from the Protocols and Sessions drop down list.
  5. Choose the transducer type and stimulus type, if not already predefined from the Protocol Setup.
  6. The Frequency range can be operated from the PC keyboard with the mouse or from the audiometer:
    • Audiometer: Frequency Down/Up 
    • PC Keyboard: Right/left arrow keys
    • Mouse mode: Left/Right arrow buttons


  7. Choose the intensity:
    • Audiometer: Use the Right wheel
    • With PC keyboard: Use the up/down arrow keys
    • Mouse mode: Up/Down arrow buttons

Presenting the stimuli:

    • Audiometer: Use the Tone Switch
    • PC Keyboard: Press on the space bar or left Ctrl button
    • Mouse mode: Hover the mouse over the Stimuli button

If masking is necessary:

    • Turn on masking in Channel 2 by ensuring that the desired transducer is selected for non-test ear
    • Ensure that the word Masking is highlighted in orange
    • Choose Rev to present the masking noise continuously
    • It is also possible to turn on Auto masking or Masking help

It is possible to define the output of channels for each protocol from the protocol settings.

June 2016

Description 
Pediatric noise is a special noise stimuli that can be used as an alternative for pure tones, warble tones and narrow band noise. The use of pediatric noise is useful during sound field testing and visual reinforcement audiometry (VRA) as it helps to avoid standing waves as well as maintain the child’s interest during testing. In additional it is useful in other assessments, which requires narrow band noise such as pitch matching and minimum masking level.

Pediatric noise addresses the two problems related to the use of narrow band noise.

1. Pediatric noise is calibrated in dB Hearing Level.

In comparison, the narrow band noise is calibrated for effective masking of tonal sounds of the same dial setting. Practically speaking it means that the narrow band noise is a few dB louder than what is required for threshold measurements.

2. The shape of pediatric noise makes it frequency specific.

While the plateau of the pediatric noise and narrow band noise are of the same width, the pediatric noise has very steep slopes, 100dB/octave vs. 12dB/octave respectively. In case of sloping hearing losses, the use of pediatric noise will not result in off-frequency listening.

Below graph illustrates the shape of the pediatric noise at 1000Hz.

Required Accessories

  • Headphones, insert phones or free field setup (FF)
  • AC40 

How to select pediatric noise
Ped noise can be run ad stand-alone on the audiometer or via Diagnostic Suite.

  1. On the standalone device, press Tests and use the wheel to select PED: pediatric noise.
    When in the PED test screen, the channel 1 Warble button will flash slowly, to indicate that the stimulus used is the pediatric noise. While using this protocol, the audiometer allows toggling from pediatric noise to tone, warble tone and back to pediatric noise.
    Note: If operated through Diagnostic Suite, pediatric noise (PED) will be available from the main tone screen in the selection of input.

  2. Conduct threshold evaluation using the pediatric noise for the desired audiometric evaluation method.

June 2016

Description
The Weber test distinguishes between conductive and sensor neural hearing loss through use of a bone conductor. Use the indications to show where the tone is perceived.

Required Accessories

Test procedure

  1. Press Tests – Weber to enter the Weber test screen.
  2. Place the bone conductor on the forehead of the patients and instruct them to tell you if the tones presented are heard better to the Right, left, Centre or not heard at all.
  3. Present a tone at a level of 10 dB above the worst BC. You can select whether you want a tone or Warble stimulus pressing the hardkey Tone/Warble on the device.
  4. Await response from the patient and click on the corresponding soft button.

 

Weber results
If the patient hears the tone better in the poorer ear, the hearing loss is conductive. If the tone is heard better in the better ear, the hearing loss is sensor neural at the given frequency. 

June 2016

Description
Interacoustics masking help is available to make it easier to decide on a safe and correct masking intensity. When masking help is activated, a status light on channel 2 indicates if masking is applied correctly. 

 Masking help is activated by selecting the icon with the mask.

 Grey indicates that the masking help is not active. Green indicates that masking is correctly applied. 

 Optionally, the masking help can give a suggested masking level. The example here shows that 85 dB, but also 75dB is within the safe masking range.

Amber indicates that masking is recommended differently. There is either too much or too little masking.

Purple indicates that masking would be recommended, but is not practically possible.

Note: The masking feature is only available in the Diagnostic Suite – and not on the audiometer as a standalone.

Recommendations
Because several masking intensities will usually be correct, experienced audiologists are recommended to use the masking help without displaying the recommended masking level.

When measuring the second ear, more information becomes available and it is not guaranteed that the earlier measurements are still correct. By measuring the best ear first and completing air conduction on both ears before measuring bone conduction, most errors can be avoided.

Clinicians do often not apply masking for bone conduction in the instance where the air-bone gap is less than 10dB in the better ear. Against general practice, masking help will always recommend that masking is needed in these cases.

June 2016

 Interacoustics auto masking is available to ease the effort required in order to mask with correct masking levels. When auto masking is enabled, channel 2 is controlled by the system and is set to the appropriate intensity level.

 Auto masking is activated by selecting the icon that shows the mask with letter A. 

 Green indicates that masking is correctly applied.

 Amber indicates that masking is recommended louder and that extended range needs to be activated to allow setting channel 2 to the correct level.

 Purple indicates that masking would be needed, but is not possible practically.

Note: The auto masking feature is only available in the Diagnostic Suite – and not on the audiometer as a standalone.

Recommendations
Be aware that patients require proper instructions before audiometry with masking is undertaken. The switching on and off of the masking noise may be uncomfortable to some patients and cause them to become more fatigued. In some cases (when testing young children, some elderly patients or difficult to test patients), it is recommended not to use masking because confusion about the application of masking noise may lead to false responses.

When measuring the second test ear, more information becomes available and it is not guaranteed that the earlier measurements are still correct. By measuring the best ear first and completing air conduction on both ears before measuring bone conduction, most errors can be avoided.

Be careful when storing thresholds where masking was not possible. Masking not possible means that the risk for crossover hearing is high. In these cases it is recommended to store a no-response at the loudest intensity where masking was still possible (by pressing the N key).

Additional information
The masking help calculates answers to the following questions:

  • Is masking required?
  • Is the masking level too low?
  • Is the masking level too high?
  • Is masking impossible?

Terminology

AC AC test ear
ACc AC contra
BC BC test ear
BCc BC contra
IaA  Minimum interaural attenuation
IaAc  Minimum interaural attenuation contra transducer
Dial Dial setting test ear
Dialc Dial setting contra (masking level)

Is masking required?
Masking is recommended when the presentation at the test ear can be heard by at the contralateral side, or in a formula:

Dial – IaA ≥ lowest of ACc and BCc

Is the masking level too low?
The applied masking level is too low when the applied masking level does not match the intensity at which the test signal is heard in the contralateral ear, or in a formula:

Dialc – (ACc – BCc) < Dial – IaA

Is the masking level too high?
The applied masking level is too high when the masking level is so loud that it potentially is heard by the test ear, or in a formula:

Dialc – IaAc ≥ Dial – (AC – BC) when testing air conduction
Dialc – IaAc ≥ Dial when testing bone conduction

Is masking impossible?
Masking is not possible when the needed masking level results in overmasking at the same time: 

Dial + (ACc – BCc) – IaA ≥ Dial – (AC – BC) + IaAc  when testing air conduction
Dial + (ACc – BCc) – IaA ≥ Dial + IaAc  when testing bone conduction

or when the needed masking level is higher than the maximum level of the masking transducer:

Dial + (ACc – BCc) – IaA > maximum available Dialc

Recommended masking intensity
The masking help can indicate a recommended masking intensity. If masking is indeed required and also possible, the recommended masking intensity is given by the minimum required masking level plus a fixed preferred amount:

Recommended Dialc = Dial – IaA + (ACc – BCc) + preferred additional amount.

The recommended masking level is adjusted for values that cannot be reached by the masking transducer due to maximum values.
When the auto masking feature is used, masking intensities are set to the recommended intensity.
Of course if “extended range” is not switched on, the masking intensities are thereby limited accordingly.

Frequency specific inter-aural attenuation
The inter-aural attenuations used by the masking help are frequency specific and can be customized in the setup. The following table shows the default inter-aural attenuation values (IaA). These are partly based on recommendations from the Handbook of Clinical Audiology and are otherwise slightly more conservative then recent publications and will therefore allow for appropriate decision making.

Frequency(Hz)

125 250 500 750 1000 1500 2000 3000 4000 6000 8000
IaA Headphones (dB) 35 40 40 40 40 40 40 45 50 50 50

IaA Inserts (dB)

50 50 50 50 50 50 50 50 50 50 50

IaABone(dB)

0 0 0 0 0 0 0 0 0 0 0

Recommendations
Experienced audiologists are recommended not to use the option of viewing a suggested masking level.

The masking help indicates if masking is performed correctly with the information given at the time of the measurement. When measuring the second ear, more information becomes available and it is not guaranteed that the earlier measurements are still correct. By measuring the best ear first and completing air conduction on both ears before measuring bone conduction, most errors can be avoided.

Although clinicians do often not apply masking for bone conduction in the instance where the air-bone gap is less than 15dB in the better ear, it can be recommended to apply masking to make the measure ear specific. Despite that an experienced clinician would disagree, the masking will, in these cases recommend, that masking is needed. This figure illustrates such a situation. 

 

 
June 2016

The purpose of this document is to provide a quick guide for basic functions of the AC440 Audiometry modules for the Affinity 2.0/Equinox 2.0 and Callisto™ suites. This Quick Guide will focus on Tone Audiometry as well as a basic introduction to the various icons, tools and menus available.

Starting up the AC440 Module

  1. Launch the Affinity 2.0/Callisto™ Suite from Noah or OtoAccess™.
  2. Click on the AUD tab on the upper right hand side of the screen.
  3. Click on the  icon to launch the tone audiometry screen, if Tone audiometry is not the default screen.
  4. Select the desired Audiometry protocol from the “Protocols and Sessions” drop down list.

Conducting Tone Audiometry
 

  1. Choose the transducer type.
  2. Choose the Stimulus type.
  3. Choose the test frequency :
    •  PC Keyboard: right/left arrow keys.
    •  Mouse mode: Left/Right arrow buttons.
  4. Choose the intensity:
    • With PC keyboard: use the up/down arrow keys.
    • Mouse mode: Up/Down arrow buttons.
  5. Presenting the stimuli
    • PC Keyboard: press on the space bar or left Ctrl button.
    • Mouse mode: hover the mouse over the Stimuli button.
  6. If masking is necessary:
    • Turn on masking in Channel 2 by ensuring that the desired transducer is selected for non-test ear.
    • Ensure that the word “Masking” is highlighted in orange
    • Choose “Rev” to present the masking noise continuously.
    • It is also possible to turn on Automasking or Masking help1.

Navigation: Tools and functions

  1. Menu: Click on Menu to access other Audiometry Special tests by going to MenuTests.

  2. Protocols and Sessions: Choose the desired test and choose the session to display. Current Session is always the active session. Highlight and select older sessions to be displayed on the active audiogram for comparison.

  3. Buttons: Access various tools and features for Tone Audiometry, including High Frequency Audiometry, Multifrequency Audiometry, Automasking, Masking Help and many others.

  4. Talk and Monitor: activate/deactivate the Talk Forward and Monitor during testing.

  5. Counseling Overlays: Activate/deactivate useful tools when counseling patients about hearing loss.

  6. Test symbols: Choose from the available symbols to display on the audiogram, now also including the tinnitus symbol.

  7. Comments/Report Editor: Use this feature to add comments relevant to the session.

  8. Click on  to collapse/minimize the Tools and Function task bar.

  9. Right Click on the menus (except on protocol and sessions) to show/hide the various tools and function.


For a more detailed description of how to use the AUD440 module, please refer to the following documents:


For more information on the Automasking/Masking Help, please refer to the Quick Guide, available on www.interacoustics.com

December 2013

Hearing Aid Fitting

Introduction
The Real Ear to Coupler Difference (RECD) is a measurement that accounts for the decibel difference across frequencies between SPL measured in the coupler and the SPL measure in the real ear, produced by the same transducer generating the same signal. This ensures that information about the patient’s occluded ear canal characteristics is obtained.

Due to the physically smaller size of the ear canals for infants and children compared to adults, and because it would be very difficult to do real-ear verification on them, the RECD is an important measurement in the pediatric hearing aid fitting process. It enables clinicians to verify the frequency/gain characteristics of the child’s hearing aid while it is attached to the 2cc BTE coupler, without the need to have the child’s ear physically present. Since children have physically smaller ears than adults, and smaller ears equals higher SPL, not taking the RECD into account would likely lead to over-amplification. For more information on RECD and the recommended guidelines for pediatric hearing aid fittings, please refer to the references at the end of this document.

Measuring the RECD
There are two ways of measuring the RECD: with the patient’s ear mould or with the SPL60 RECD probe tip.
Measuring with ear moulds will be a bit more precise than measuring with the SPL probe, however; in situations where a quick measurement is needed, using the SPL probe will be much quicker than measuring with the ear mould. In situations where no measurement can be obtained, it is recommended to use age appropriate, predicted RECD values. Instructions for all three methods are detailed below.

RECD measurement with earmold
Items required:

  • The Affinity 2.0 or Callisto™ with Coupler Base
  • The REM440 software
  • An REM headset/reference microphones
  • A probe tube
  • An ear mould
  • An RECD tube found in the SPL60 Probe tip set, which will be connected the ear mould tube via a tube-nipple
  • 2 cc coupler connected to an adaptor for the BTE

Figure 1: Measuring the RECD with an ear mould with Affinity 2.0 and Callisto™.

  1. Launch the Affinity 2.0 or Callisto™ software from your patient management system, Noah or OtoAccess™ and click on the REM440 tab
  2. From the Protocols and Sessions drop down list, choose a protocol that includes the RECD (ex: Pediatric Aided Response)
  3. Connect the thicker RECD probe tube to the larger metal spout on the REM headset and connect the regular probe tube to the smaller metal spout
  4. Calibrate the probe tube by clicking the calibrate icon and selecting “Regular Probe”
  5. Connect a tube nipple to the other end of the RECD probe tube
  6. Connect the tube nipple to the BTE tubing attached to the 2cc BTE Adaptor
  7. Click on the RECD test and click start to measure the coupler portion of the RECD measurement
  8. Once the coupler measurement is done, the software will prompt to measure the ear portion of the RECD. Disconnect the tube nipple from the RECD probe tube and connected to the ear mould tubing
  9. Proceed with otoscopy, ensuring the ear canal is clear. Place the probe tube inside the patient’s ear and position the ear mould, connected to the RECD probe via tube nipple, in the ear canal
  10. Continue with the ear portion of the RECD. The two measurements will be on the screen and the difference will be calculated automatically
  11. The RECD can now be used for the hearing aid fitting. The RECD can be imported, if that feature is supported, manually into the hearing aid software. The fitting will be recalculated while taking the RECD into account1 . To view the RECD values, click on Table View
  12. To proceed with the hearing aid verification, click on the REAR button; the software will automatically go into the coupler mode and it will then be possible to proceed with the verification. The default fitting formula will be DSL v5 Pediatrics. Use the hearing aid software to fine tune the hearing aid and to ensure that the output is matching the DSL targets for soft, average, and loud, using a speech stimuli (like the ISTS). Measure the MPO to ensure that the output for loud sounds is not hitting the UCL.

RECD Measurement with SPL60 Probe
Needed items:

  • The Affinity 2.0 or Callisto™ with Coupler Base
  • The REM440 software
  • An REM headset/reference microphones
  • A probe tube
  • The SPL60 probe tip
  • Impedance probe tips
  • 2 cc coupler connected to an adaptor for the BTE

Figure 2: Measuring the RECD using the SPL probe with Affinity 2.0 (a) and Callisto™ (b)

  1. Launch the Affinity 2.0 or Callisto™ software from your patient management system, Noah or OtoAccess™ and click on the REM440 tab
  2. From the Protocols and Sessions drop down list, choose a protocol that includes the RECD (ex: Pediatric Aided Response)
  3. Click on RECD. Right click and select “Settings. A window will pop up and ensure the checkbox “use In Situ SPL probe” is ticked off. This will tell the software that the SPL60 probe is being used rather than the ear mould2
  4. Connect the SPL60 Probe tip to the REM headset; thicker tube to the larger metal spout, regular probe tube to the thinner metal spout
  5. Calibrate the SPL60 probe by clicking the calibrate icon and selecting “SPL Probe”
  6. Connect the RECD adaptor to the 2cc coupler and attach to the coupler microphone
  7. Click on the RECD test and click start to measure the coupler portion of the RECD measurement
  8. Once the coupler measurement is done, the software will prompt to measure the ear portion of the RECD. Remove the probe tip from the coupler.
  9. Proceed with otoscopy, ensuring the ear canal is clear. Select an appropriately-sized probe tip and place it in the patient’s ear
  10. Continue with the ear portion of the RECD. The two measurements will be on the screen and the difference will be calculated automatically

Using age appropriate predicted RECD values

If it is impossible to get an RECD measurement (ex: child is crying or uncooperative), it is recommended to use age appropriate predicted RECDs.

  1. Launch the Affinity 2.0 or Callisto™ software from your patient management system, Noah or OtoAccess™ and click on the REM440 tab
  2. From the Protocols and Sessions drop down list, choose a protocol that includes the RECD (ex: Pediatric Aided Response)
  3. Select RECD
  4. Right click on the RECD and select “Show Predicted Curve”. A window will pop up, asking to choose the age and to choose the type of prediction: “ear mould” or “tip”

Own Mould versus SPL Probe
Whether the RECD is performed using the client’s own ear mould or the SPL probe may have an effect on the result. The benefit of using the client’s own ear mould is that the measurement will reflect your client’s actual residual volume whereas the SPL probe only provides an estimate. However, you may be in a situation where the ear mould is nonexistent, broken, or has an extremely bad fit. Furthermore, you might need to conduct measurements on children not willing to co-operate. In these situations the SPL probe offers the benefit of easy probe placement and measurement.

Below, see two RECD measured in the same ear using the SPL probe and own ear mould respectively. Note: the differences between the two ways of measuring. As can be seen above the curve measured with the client’s own ear mould is below 0 in the low frequencies. This may be due to ear mould effects such as the tightness of the fit and venting and in the insertion depth of the SPL probe or ear mould.

Using the RECD in the hearing aid fitting
The RECD can now be used for the hearing aid fitting. The RECD can be imported, if that feature is supported, manually into the hearing aid software. The fitting will be recalculated while taking the RECD into account3. To view the RECD values, click on Table View.

To proceed with the hearing aid verification, click on the REAR button; the software will automatically go into the coupler mode and it will then be possible to proceed with the verification. The default fitting formula will be DSL v5 Pediatrics. Use the hearing aid software to fine tune the hearing aid and to ensure that the output is matching the DSL targets for soft, average, and loud, using a speech stimuli (like the ISTS). Measure the MPO to ensure that the output for loud sounds is not hitting the UCL.

Visible Speech Mapping can also be used for coupler based fittings. This can be done by choosing the Visible Speech Mapping in the REM module, rather than the REM440 module it self. Note that Visible Speech Mapping requires a separate license.

For more information, please consult the Affinity 2.0 Additional Info and Callisto™ Additional Info documents, available on our website www.interacoustics.com.


1Not all hearing aid manufacturers support RECD imports. Contact the hearing aid manufacturers if unsure.

2If always using the SPL probe rather than ear moulds, it is possible to create a protocol to ensure that the “Use the insitu SPL probe” option is always ticked off. For information on how to create protocols, please refer to the Instructions for Use or Additional Info manuals for Affinity 2.0 or Callisto™.

3Not all hearing aid manufacturers’ software support the import of RECDs. If unsure, check with the hearing aid manufacturer.

References
Bagatto MP. Optimizing your RECD measurements.The Hearing Journal 2001; 54: 32, 34-36.

Bagatto MP. The Essentials of Fitting Hearing Aids to Babies. Seminars in Hearing 2013; 34:1, 19-26

Bagatto MP (2007). Learning the Art to Apply the Science: Common Questions Related to Pediatric Hearing Instrument Fitting. 

McCreery, Ryan. RECD is a Reasonable Alternative to Real-Ear Verification. The Hearing Journal 2013; 66:7, 13-14. Munro, Kevin. Integrating the RECD into the Hearing Instrument Fitting Process.

Purdy, J and Sheila, T. (2008). Measuring RECD on a Young Child. 

December 2013

This Quick Guide is intended to give a brief explanation on how to fit CROS and BiCROS type hearing aids. The instructions in this guide have been adapted from the methods stated by Hayes (2006) and Pumford (2005), links to these articles are provided at the bottom of this document.

The following points of instruction apply to the whole of this document and will aid understanding as to what is being measured in the different conditions:

  • The probe microphone is always placed in the aidable or normal hearing ear, never in the unaidable ear.
  • The patient will move position so that the loudspeaker is within the range of -900 through 00 to +900 relative to the front of the client at different stages in the procedure. Images have been used below to aid your understanding of this.
  • The reference microphone is always located on the same side of the head as the loudspeaker.

CROS Hearing Aids

The objective of this measurement is to make signals from the unaidable side of the head sound the same as signals from the side of the better or normal hearing ear.

Dedicated protocols have been created for optimum application of this test, please speak to your local distributor to get and import these for use.

  1. Calibrate and insert both probe microphones.

  2. Measurement One: Measure the REUR/REUG of the best ear with the patient at 450 or 900 to the speaker.
    Note: The CROS system is not added to the ear at this point.

    Run the ‘Better Ear REUR/REUG’ Measurement. This should lead to a curve similar to below.

    Note: Make sure that if you run your first condition at 450 then the second condition should be at -450. This is also required for measurements run at 900. If this isn’t done then the measurement curves are not comparable.

  3. Measurement Two: Move the patient so that the loudspeaker and reference microphone are to the side of the unaidable ear (-450 or -900 relative to the poorer ear). Add the CROS system to your patients ear and turn it on. You must also enable the CROS setting in your Affinity/Equinox or Callisto Suite (shown in the image below).

    Note
    : You do not need to swap earside in order to perform this measurement, all measurements are performed to the same earside from the first measurement.
    Run the ‘CROS Response’ measurement.

    The CROS Setting is available in the following location of your Suite.

    This measurement should lead to a curve similar to the below.
  4. You now need to adjust your CROS system until the REAR/REIG from the second measurement overlaps the REUR/REUG from the first measurement. Imagine the first measurement to be your target in this scenario.

    Note:
    Probe microphone measurements cannot be applied to transcranial/bone-anchored CROS fittings.

BiCROS Hearing Aids

The objective of this test is similar to what has been shown above, however there is a hearing aid on the better ear for which we need to take consideration for.
The same dedicated protocol as used in the CROS instructions above is used for optimum application of this test, please speak to your local distributor to get and import these for use.

  1. Ensure you have already Fitted the hearing aid without the CROS features enabled to a suitable algorithm based on the patients scenario (i.e. NAL-NL1, NAL-NL2 or DSL).

  2. Calibrate and insert both probe microphones.

  3. Measurement One: Measure the REUR/REUG of the best ear with the patient at 450 or 900 to the speaker. Remember to ensure the hearing aid is inserted and enabled in this scenario.

    Run the ‘Better Ear REUR/REUG’ Measurement. This should lead to a curve similar to below.

    Note: Make sure that if you run your first condition at 450 then the second condition should also be at 450. This is also required for measurements run at 900. If this isn’t done then the measurement curves are not comparable.

  4. Measurement Two: Move the patient so that the loudspeaker and reference microphone are to the side of the unaidable ear (-450 or -900 relative to the poorer ear). Enable the CROS system and the CROS setting in your Affinity/Equinox or Callisto Suite.

    Note: You do not need to swap earside in order to perform this measurement, all measurements are performed to the same earside from the first measurement.
    Run the ‘CROS Response’ Measurement.

    The CROS Setting is available in the following location of your Suite.

    This measurement should lead to a curve similar to the below.
  5. You now need to adjust your CROS system until the REAR/REIG from the second measurement overlaps the REUR/REUG from the first measurement. Imagine the first measurement to be your target in this scenario.

    Note: Probe microphone measurements cannot be applied to transcranial/bone-anchored CROS fittings.

Further Reading
For more information on this topic then please see the following articles:

Hayes, D. (2006). A Practical Guide to CROS/BiCROS Fittings.
Pumford, J. (2005). Benefits of probe-mic measures with CROS/BiCROS fittings. 

May 2017

The purpose of this Quick Guide is to give clinicians a short introduction to Visible Speech Mapping during the hearing aid fitting process and patient counseling.

Introduction
Verification of the hearing aid fitting is a very important part of the fitting process. To try to make this process a bit easier, rather than using traditional real-ear measurements, hearing care professionals can use the Visible Speech Mapping modules in the Affinity 2.0 and Callisto™ suites. Visible Speech Mapping is an intuitive tool which helps hearing care professionals better explain the benefits of amplification.

Getting Started
Speech Mapping is a Real Ear Aided Response (REAR) measurement; therefore the same equipment that is needed for a REAR is also needed. To start, follow the steps below.

  1. Launch the Affinity 2.0 or Callisto™ Suite through your patient management system, NOAH, OtoAccess® orStandalone.
  2. Enter/Select an audiogram from NOAH or from the AUD module (if using Standalone). If no audiogram is entered or selected, no targets will be displayed.
  3. Launch the REM module by clicking on the REM tab.

Prepare the patient for REM

  1. Connect the REM headset to the Affinity 2.0 or Callisto™ hardware.
  2. Connect a probe tubes to the REM reference microphones.
  3. Click on the Tube Calibration button and follow the instructions on the screen.
  4. Position the patient approximately 0.5 meters from the REM loudspeaker.
  5. Perform otoscopy to ensure the ear canal is clear.
  6. Snap the REM headsets on the REM headband and place on patient’s ear.

Measurement Steps

Figure 1: the Visible Speech Mapping screen

  1. Choose the Visible Speech Mapping protocol from the drop down menu.
  2. Choose the appropriate options with in the Fitting Prescription Settings window, which will appear automatically when the Speech Mapping protocol is chosen:The fitting formula can also be changed by expanding the “advanced view” option (#2 above).
  1. To verify the fitting, select the ISTS signal (to use a calibrated speech-like signal for verification).
  2. Click on the Visible Speech Mapping button at the bottom left of the screen. If using an Open Fitting configuration, click on the “Calibrate for Open Fit” before proceeding with verification.1
  3. Click on the slider to adjust the input level of the ISTS signal; suggested start level is 65 dB SPL. Click START.
  4. Repeat step 5 using soft and loud levels; suggested levels are 50-55 dB SPL and 75-80 dB SPL, respectively.
  5. Change the Input signal to Warble Tone. Using the slider (Figure 1, number 5) to increase the level of the signal to 90. Click START to measure the MPO.

    Note: If choosing DSLv.5, the MPO targets will automatically appear, since the UCL thresholds are always predicted from the audiogram. If choosing NAL-NL1 or NAL-NL2, the UCL thresholds need to be entered in the audiogram screen for the MPO targets to be generated.

  6. Fine tune the hearing aid if necessary, to match the target. Use the On Top mode button minimize the REM screen and to bring it “on top” of the hearing aid manufacturer software.
  7. Counsel the patient, using the tools described below.

Counseling Elements in Visible Speech Mapping

 

The Speech Spectrum: used to counsel regarding audibility.

  • For example: showing the patient that soft sounds (lower line on image to the left) are below the thresholds could help counsel on expectations of hearing aid performance.

  • It could also help HCPs demonstrate the effects of fine tuning the HI.

 

Using Live Speech Mapping or Environmental sounds.

  • Select the “Live Voice” feature to demonstrate the effects, benefits and limits of amplification.

  • Use a whisper to show how the hearing aid reacts to it.

  • Ask the significant other to stand far away from the hearing instrument user and talk; this helps demonstrate some of the limits of the hearing instrument.

  • Play environmental sounds to demonstrate how they sound with the hearing aid.

 

Counseling overlays.

  • Use visuals to help explain the hearing loss to patients.

  • Adding visual information helps understanding of amplification and hearing loss.

  • Choose from “Familiar Sounds”examples, Phonemes and Speech Banana.

 

Unaided vs Aided.

  • Easily visually demonstrate the difference between unprocessed vs processed/amplified sound.

  • Can demonstrate the effect of adaptive hearing aid features.

    • Frequency Shifting.

    • Noise reduction.

 

Speech Intelligibility Index.
Use this to visibly show, using a percentage, improvement in speech intelligibility from unaided to aided.

 

Adaptive Feature example 1: Demonstrating Frequency Shifting.

  • Red curve: Unaided vs Aided, normal amplification.

  • Blue curve: Unaided vs Aided after activating a frequency shifting algorithm

 

Adaptive feature example 2: Demonstrating Noise Reduction.

  • Red Curve: Unaided and Aided with Noise Reduction feature OFF.

  • Blue Curve: Unaided and Aided with Noise Reduction feature set to MAX.

 

Dynamic range.

  • The dynamic range is the range between the softest sound the ear can detect and the loudest sound the ear can tolerate (thresholds and UCLs).

  • Use the Speech Mapping graph to explain the consequences and limitations of narrowed dynamic ranges.

  • Demonstrate the difference between a normal dynamic range (normal hearing to UCL) and a narrowed dynamic range (hearing loss to UCL).


1For instructions on how to do the open fitting calibration, please refer to the REM Quick Guide

December 2013

The purpose of this document is to provide a quick guide for the REM procedure stated by the British Society of Audiology (BSA) for the REM440 Real-Ear Measurement module in the Affinity2 and CallistoTM Suites. This Quick Guide will focus on the method and order of the REM measurements specified by this guideline.

Introduction
The BSA Clinical Practice Guidelines recommend using the NAL-NL1/NAL-NL2 fitting formulae when performing Adult hearing aid verification. The choice between the use of the REIG (insertion gain) or the REAR (aided response) is at the audiologists’ discretion as both methods are accepted verification methods. This Quick Guide assumes that the hearing aid has been programmed accordingly based on patients’ needs and hearing loss.

Preparation

  1. Enter/Select an audiogram from Noah or from the AUD module. If no audiogram is entered or selected, no targets will be displayed.
  2. Connect probe tubes to the REM reference microphones.
  3. Click on the Tube Calibration button  and follow the instructions on the screen, this process ensures that the probe tube is made acoustically invisible – enabling an effective display of the actual gain achieved at the tympanic membrane by the hearing aid.
  4. Position the patient approximately 0.5 meters from the REM loudspeaker.
  5. Perform otoscopy to ensure the ear canal is clear.
  6. Snap the REM headsets on the REM headband and place on patient’s ear.

Verification using Insertion Gain (REM Adult UK)

  1. Choose the REM Adult UK protocol, this is correctly configured according to the BSA Guidelines.
  2. Choose the appropriate options with in the Fitting Prescription Settings window, which will appear automatically when a REM protocol is chosen:

It is here that you will configure your prescription settings to acknowledge aspects of the patients amplification setup, i.e. venting, mono/binaural, compression method, whether you wish to base your target on their Bone values for mixed and conductive losses. etc.

  1. Select the desired verification signal.
    It is advised that a calibrated signal such as ISTS is applied. This ensures that the Long Term Average Speech Spectrum (LTASS) level is maintained and is known to provide consistent stimulation intensity throughout the duration of the measurement.
  2. Insert the probe tube in the patient’s ear without the hearing aid, you should aim to have this at a length of 27mm from the patients tragus, this ensures that the tube is close to the ear drum.
  3. Click on REUR, and click on START to measure the Real-Ear Unaided Response
    (Note: The REUR is a required measurement as it is used for the calculation of the REIG, it enables consideration for the patients’ natural ear canal resonance).
    Effective placement of the Probe Tube is achieved when the response is between 0dB and -5dB at 6kHz. Reposition the tube and re-perform the measure if you cannot achieve this, it will lead to improved measures.
  4. Place the hearing aid in the patient’s ear, but ensure that it is muted.
  5. Click on REOR and click on START to measure the Real-Ear Occluded Response. The REOR shows the occluding effect of the ear canal in relation to the patients’ natural ear resonance. It can also be used as an effective method of checking whether you are blocking the probe tube ahead of beginning your measurements.
  6. Measure the insertion gain at the desired input level.
  7. Fine tune the hearing aid if necessary. Use the On Top mode button  to minimize the REM screen and to bring it “on top” of the hearing aid manufacturer software.
    BSA guidelines advise that you begin at 65dB and then adjust softer (50dB) then louder (80dB) and finally re-check 65dB to ensure that amendment of the soft and loud trimmers haven’t drastically altered the response of this stimulus outside of the BSA recommended range.

Verification of Open Fittings (REM Adult Open Fit UK)

  1. Choose the REM Adult Open Fit UK protocol:
  2. Choose the appropriate options within the Fitting Prescription Settings window, which will appear automatically when a REM protocol is chosen.
  3. Select the desired verification signal.
  4. Insert the probe tube in the patient’s ear without the hearing aid.
  5. Click on REUR, and click on START to measure the Real-Ear Unaided Response 
    (NOTE: The REUR is a required measurement as it is used for the calculation of the REIG).
  6. Perform the Open Fit calibration:

Open Fit Calibration steps:

  1. Position the probe tube in the patient’s ear canal.
  2. Place the hearing aid, connected to the hearing aid fitting software, inside the patient’s ear.
  3. MUTE or SWITCH OFF the hearing aid.
  4. Choose the stimulus (ex: ISTS) and click on START to perform the calibration. The calibration values will now be stored inside the system and the reference mic will be turned off.
  5. UNMUTE the hearing aid
  6. Proceed with Real Ear Measurements.
    The purpose of this process is to ensure that the REM system is not actively regulating the output of the stimulus speaker. The reason why we want to disable this is because there is sound leakage from the Open Fitting onto the REM headset’s reference microphone. Therefore the stimulus delivered is inaccurate. By storing the distance from the speaker via this measurement the speaker can then stimulate according to that fixed point. It is important to ensure the patient maintains their position during this type of measurement.

Verification using the REAR protocol

  1. Choose the REM Adult Aided Response UK protocol:
  2. Choose the appropriate options with in the Fitting Prescription Settings window, which will appear automatically when a REM protocol is chosen:
  3. Select the verification signal.
  4. Measure the aided response for soft, average and loud
    (Note: with REAR measurements, it is not necessary to measure the REUG/REUR. However, some clinicians like to use the REUG/REUR as an indication for adequate probe placement.).
  5. Fine tune the hearing aid if necessary. Use the On Top mode button  to minimize the REM screen and to bring it “on top” of the hearing aid manufacturer software.

For a more detailed description of how to use the REM440 module, please refer to the following documents:

December 2013

Introduction
The purpose of this Quick Guide is to provide guidelines on how to conduct basic technical measurements of hearing instruments using the HIT440 module for the Interacoustics Affinity 2.0 hearing aid analyzer.

Note: Hearing instruments needs to be in FULL ON GAIN MODE/TEST MODE in order to compare the results to the hearing aid manufacturers’ technical data sheets. Each hearing aid manufacturer has a different way of accessing this Test Mode. Please check with the hearing aid manufacturers for instructions on how to program the hearing aid into TEST MODE.

  1. Launch the Affinity2 Suite from your patient management system, Noah or OtoAccessTM.
  2. Click on the HIT tab to launch the HIT440 module.
  3. If comparing to manufacturers’ technical specification, ensure that the hearing aid is in FULL ON GAIN MODE.

Setup 

BTE hearing instrument
Required Items:

  1. The Affinity 2.0 hardware.
  2. The Affinity 2.0 Suite with the HIT440 module.
  3. A coupler microphone.
  4. A coupler (most common is 2cc coupler).
  5. The BTE Adaptor for the coupler.
  6. The reference microphone 2 (included in Affinity 2.0 test box).
  7. Earmold Tubing to connect the hearing instrument to the BTE adaptor/coupler.

Positioning the BTE in the test chamber:
Place the coupler tube pointing straight forward and the microphone at the cross. (Multiple microphones: Place the half-way point between the microphones at the cross).

ITE/Open Fittings/Receiver in the ear
Required Items:

  1. The Affinity 2.0 hardware
  2. The HIT440 software.
  3. A coupler microphone.
  4. A coupler (usually 2cc).
  5. An ITE adaptor for 2cc coupler.
  6. A reference microphone.
  7. Blue putty to secure the hearing instrument to the 2cc coupler.

Positioning the ITE hearing instrument:
Place coupler at the back with hearing aid facing forward and the microphone at the cross. (For multiple microphones, rotate the hearing aid to get equal horizontal positioning of the mic inputs). Connect the ITE adaptor to the 2 cc coupler and attach the hearing aid using blue putty.
ITE pick-up coil test: For this particular test only: Position the coupler for maximum sensitivity of the coil.

Positioning the Open Fit/Receiver in the ear hearing instrument:
Connect the ITE adaptor to the 2 cc coupler. Remove the tip/dome from the hearing instrument and attach it to the ITE adaptor using the blue putty. Place the coupler tube pointing straight forward and the microphone at the cross.

Test procedure:

  1. Position the hearing aids and reference microphone as shown in the pictures above.
  2. Select the desired test protocol in the List of Protocol
  3. Select Test Ear.
  4. Select START

  5. Please wait for all tests of the selected protocol to be performed.
  6. Save by clicking “Save” icon

Comparing to the manufacturers specification sheets
Most hearing aid manufacturers use known international standards, such as the ANSI or IEC for their specification sheets. The same standard can usually be selected in the HIT440 software.

Testing for battery drain

  1. Insert the battery pill inside the hearing aid (example below).
  2. Connect the battery pill into the red socket in the Affinity 2.0
  3. If the test is included in the test sequence, it will be measured automatically.

For more information on HIT440, please refer to the Affinity 2.0 Additional Information document.

December 2013

The purpose of this document is to provide a quick guide for the Binaural REM feature found in the REM440 Real-Ear Measurement module in the Affinity 2.0 and Callisto™ Suites. This Quick Guide will focus on the method and order of performing measurements using this function.

Introduction
Interacoustics are pleased to announce the availability of a Binaural REM feature in the Affinity 2.0 and Callisto™ Suites. This feature will allow you to perform Real Ear Measures in a much faster procedure and allow you to view the activity in each ear simultaneously.

Preparation

  1. Enter/Select an audiogram from Noah or from the AUD module. If no audiogram is entered or selected, no targets will be displayed.

  2. To enable Binaural REM measurements in the REM module you will need to Right click on the ear selector icon. This will then show a binaural icon and a popup to alert the user when using this function.

    Due to the way in which this feature has been implemented you will not need to recreate new protocols to use this function. It uses the settings you already have in your existing protocols.

    Please note: when running measurements of this type you will only be using one reference microphone to monitor the signal from the speaker. This is the right microphone by default but it can be swapped to the left microphone by using the ‘use opposite reference microphone’ button. 

     

    It is also essential that the position of the patient in relation to the REM speaker is maintained at 0° as this will ensure that the same signal intensity is reaching each ear as they are equal distance from the speaker.

  3. Connect probe tubes to the REM reference microphones.

  4. Click on the Tube Calibration button  and follow the instructions on the screen, this process ensures that the probe tube is made acoustically invisible – enabling an effective display of the actual gain achieved at the tympanic membrane by the hearing aid.

    On running the calibration you will notice that in Binaural mode there is an automated procedure to calibrate both Left and Right REM tubes sequentially, without having to manually start each individually.

  5. Position the patient approximately 0.5 metres from the REM loudspeaker.

  6. Perform otoscopy to ensure the ear canal is clear.

  7. Snap the REM headsets on the REM headband and place on patient’s ear.

  8. Choose a relevant protocol to perform your verification; in this example the default ‘Adult Insertion Gain’ protocol has been used.

     

    Note: For this example, an Insertion Gain method has been used to demonstrate the Binaural REM feature, however the feature is also compatible with protocols which perform this measurement in an Aided Response method.

  9. Once you have chosen your protocol please configure your fitting prescription settings as per your fitting.

  10. Place the REM tubes inside the patient’s ears and aim to use a marker of roughly 27mm on the probe tubes. This helps to get the open end of the tube in an optimum recording position (BSA, 2007).

  11. Begin by running the REUR measurement, this is looking at the natural acoustics of your patients ear canals, it is performed with nothing in the patients ear canals apart from the probe tubes. Your response should peak around 2-3 kHz for a normal adult response (BSA, 2007). The shape of this measurement can also be used as a quality criteria for your probe placement, the measurement should intersect the

    Horizontal axis (x-axis) at 6khz and must not be more negative than -5dB (BSA, 2007 & ISO, 2003).

  12. You can now proceed to running the REIG measurements, there are 3 different intensity measurements in this protocol but the main focus should be to fit the 65dB curve as this is the intensity for speech. 

    Please place the hearing devices into your patient’s ears along with the probe tubes for the following measurements. 

    You will notice that there is a target in these measurements; in the next step it is shown how you can amend the output of the patient’s hearing devices to meet these targets.

    Note: the default view for the Binaural REM feature is to have the left and right aided measure displayed side-by-side. However this can be swapped to an on-top comparison by pressing the button shown below, there is an example of this view below.

     

    Note: Percentile analysis can also be performed in Binaural REM, you just need to enable this setting within your Aided Response measurements protocol. Once enabled, the test screen will show you the percentile range for your output, as shown below.

  13. You will now begin fine tuning in the hearing aid fitting software to amend the output of the device to meet the prescription target.
  14. Should you wish to edit the targets when performing a binaural measurement then you should click on this icon . Doing this will open the below dialogue screen which will allow you to edit the target for each independent ear currently on the screen or input your own, i.e. a proprietary target from a hearing aid fitting software.
     
    On setting a custom target it reverts the target to a ‘Custom target’ from a previously set standard target (NAL, DSL etc.) on doing this you should input values for both ears otherwise no target will appear for the side which you haven’t entered values for.

    Note: Using this feature will remove your previous target allocation (i.e. NAL-NL2, DSLmi/o etc) from the opposite ear side, which you have not provided custom values for, because we cannot allow different prescription methods to be used on different ears independently.

  15. A nice feature in the Affinity 2.0 and Callisto™ Suites is the On-top-mode. This feature allows you to minimize the suite so that it can be placed on top of the fitting software to make it easier to fine tune and compare the output following your changes. This feature can be used on pressing the following button on the left of the Suite GUI.
  16. Once you have fine-tuned your hearing devices so that the patient is happy and have counselled them involving their opinions in the amplification of their hearing devices you can save and close the Suite and finish the session. This is done by pressing the ‘Save and Exit’ button.

Note: Binaural REM can also be used when fitting Open Fit type hearing aids. All this requires is for the ‘Open Fit Calibration’ to be run following the REUR measurement for the signal(s) you wish to use for the following measurements.

Note: Binaural REM can only be used with stimuli which do not require active referencing during the measurement. Therefore Binaural REM is not suitable for measurement with Warble Tone, Pink Noise, Random Noise, Pure tone and Narrowband Noise.

For a more detailed description of how to use the REM440 module, please refer to the following documents:


References 
BSA (2007). Guidance on the use of Real Ear Measurement to verify the fitting of digital signal processing hearing aids. Reading, British Society of Audiology.

BS ISO 12124 (2001). Acoustics: Procedures for the Measurement of real-ear acoustical characteristics of hearing aids. Geneva, International Standards Organisation.

November 2015

The purpose of this Quick Guide is to describe how to do real-ear verification of Ear Level FM systems (Oticon Amigo Star, Phonak iSense) with the Interacoustics Affinity 2.01 Hearing Aid Analyzer, using FM-specific targets.
The verification method is based on the AAA Clinical Practice Guidelines for Remote Microphone Hearing Assistance Technologies for Children and Youth Birth to 21 Years. For more information, please refer to the AAA Guidelines.

Introduction
Ear Level FM systems are intended to be used by patients who have normal or near-normal hearing and help increase the signal to noise ratio. They can be used, for example, in classroom settings for a child having learning difficulties or auditory processing disorders (APD). Typical use will include an ear-level FM receiver, coupled to a thin tube, in an open ear configuration. The steps below guide clinicians on how to perform straightforward real-ear verification of the ear level FM system, in order to verify the maximum output and the recommended volume setting for the FM receiver.

Verification Steps

  1. Prepare the patient for normal real ear:
    • Position patient in front of the Affinity loudspeaker.
    • Place the probe tube in the ear.
    • Position the ear level FM receiver on the ear.
  1. From Noah or from the Affinity suite AUD screen, enter the audiogram. The audiogram will be within the range of normal/near normal.

  2. Click on the REM tab.

  3. Once in the REM screen, select the “Ear Level, FM only” protocol from the drop down list.

  4. Place the FM transmitter microphone inside the test chamber, facing the reference microphone.

    NOTE: The test box reference microphone is the active microphone

  5. Close the lid of the test chamber.

  6. Measure the MPO:
    • Click on MPO to access the MPO test.
    • Set the FM transmitter volume control to MAX.
    • Click Start to measure the Real-Ear Saturation Response.
    • If the MPO measurement is too high, adjust the FM output.


  7. Measure the REAR and match target between 1kHz and 4kHz.
    • Select the appropriate FM-specific target:
      • FM Boom or
      • FM Chest
      •  the choice should reflect what is used with the FM system being tested
    • Measure the REAR by clicking the Start button.
    • Adjust volume control on the FM receiver to match the targets between 1kHz and 4kHz. 
  8. Re-measure the RESR/MPO at user setting.


1Affinity software version 2.4 or higher is needed for Real Ear verification of ear level FM systems

References
American Academy of Audiology (April 2011). Clinical Practice Guidelines: Remote Microphone Hearing Assistance Technologies for Children and Youth Birth to 21 Years (includes supplement A). 

Angelo, Kamilla & Fuglholt, Merethe L. (2013). Amigo Star. A New Ear-Level FM-Only Receiver. Pediatric Knowlegdge Brief.
Eiten, Leisha R. FM for Children, Chapter 7. Assessing Open Ear Edulink Fittings.

December 2013

Introduction
The purpose of this Quick Guide is to describe how to verify FM transparency of FM system using the Interacoustics Affinity1 Hearing Aid Analyzer. FM Transparency can be defined as “The condition in which equal inputs to the FM and hearing aid microphones produce equal outputs from the hearing aid.”2 The verification method is according to the AAA Clinical Practice Guidelines for Remote Microphone Hearing Assistance Technologies for Children and Youth Birth to 21 Years. For more information, please refer to the AAA Guidelines.

The FM Transparency consists of 3 easy coupler measurements:

  1. Hearing Aid alone.
  2. Hearing Aid + FM receiver attached, FM transmitter on and muted .
  3. Hearing Aid + FM receiver attached. Transmitter microphone unmuted and positioned inside the test chamber, facing the reference mic. Hearing instrument still attached to the coupler/coupler mic, positioned outside the test chamber.

Verification Steps

  1. Launch the Affinity 2.02 Suite and choose a patient, through Noah or OtoAccess™.
  2. Launch the REM module.
  3. Select the FM Transparency protocol from the drop down menu.

NOTE: FM Transparency assumes that the hearing aid has already been programmed to match the targets, according to the patient’s hearing loss and patient needs. Therefore, there is no need to show targets on the screen. Targets and Fitting prescription information will not appear on the main screen when the FM transparency is chosen.

The FM Transparency setup guide will pop up when the above protocol is chosen, instructing the HCP on how to setup for FM Transparency verification3:

Step 1: HA Alone

  1. Select the HA Alone test.
  2. Attach the hearing aid to the coupler/coupler microphone.
  3. Position the hearing aid in the test chamber.
  4. Click START to measure the output of the hearing aid (red curve).

Step 2: HA + Receiver

  1. Leaving the hearing aid attached to the coupler, attach the FM receiver to the hearing aid.
  2. Turn on the FM transmitter. Mute it.
  3. Click START to measure the output of the hearing aid (purple curve). 


Note: the two curves should be very similar to each other

Step 3: FM Mic + HA

  1. Remove the hearing aid, still attached to the coupler, from the test box.
  2. Position the FM microphone inside the test box, in front of the reference microphone.
  3. Click START to measure the output of the hearing aid when input is from the FM microphone (green curve).


Note:

  • If a significant difference is already seen between the Green curve and the Red curve, one can presume that there is a problem with the FM microphone.
  • Ensure that the test is conducted in a quiet environment, since the hearing aid is outside the test box and the HA microphones are still active.

Step 4: Calculate the average difference

  1. Click on the table mode icon  to activate Table Mode.
  2. Once in table mode, calculate the difference between 750 Hz, 1000 Hz and 2000 Hz and
  3. Calculate the average.
  4. If the average is 2 dB or less, FM transparency is achieved.
  5. If the average is more than 2 dB, adjust the FM.

Example 1

*Average difference is less than 2 dB, therefore transparency is achieved

Example 2

*Average difference is less than 2 dB, therefore transparency is achieved


1To have access to the dedicated FM Transparency test, Affinity suite 2.4 or higher is needed.
2American Academy of Audiology (2011).
3The FM Transparency test is a coupler test, therefore the protocol will start up in coupler mode by default. Coupler mode is indicated by a hearing instrument attached to a coupler on the main screen.

References
American Academy of Audiology (April 2011). Clinical Practice Guidelines: Remote Microphone Hearing Assistance Technologies for Children and Youth Birth to 21 Years (includes supplement A). 

Fernée, Ben Zalm (2012). FM Verification Made Easy 

December 2013

This Quick Guide is indented to provide information on how to conduct directional testing of hearing aids, using the REM440 module of the Affinity 2.0 and Callisto™ Software Suites.

Directionality Test using REM440

Directionality Test using Real Ear Measurements

  1. From your patient management system, Noah or OtoAccess™, launch the Affinity 2.0 or Callisto™ suites.
  2. Launch the REM440 module by clicking on the REM tab.
  3. Prepare the patient for Real Ear Measures.
  4. Calibrate the probe tube.
  5. If fitting an open hearing instrument, perform Calibrate for open fit.
  6. Ensure that the correct Ear is selected.
  7. To activate the Directional Test, go to: Menu│Setup│Show/hide protocolsUSStandard Directionality. Insert the checkmark inside the box in front of Standard Directionality. This will ensure that the Directionality test is available from the list of protocols drop down menu1.
  8. Choose the preferred Stimulus in the corresponding dropdown list.
  9. Change the input level using the slider if desired.
  10. Click START and follow the instructions on screen.
  11. Place the client in front of the loudspeaker as shown on the picture. Click OK and front microphone curve will be recorded. New instructions will immediately appear. Turn the client around and click OK.

To add the directionality test to an existing protocol:

  1. Go to Menu │Setup │REM440 Setup.
  2. Choose a protocol to copy (ex: Adult Aided Response) from the drop down list.
  3. Click New to create a new protocol.
  4. Click Yes when the software asks if you want to copy the currently selected protocol2.
  5. Rename the Protocol.
  6. Add the Directionality test to the existing protocol.
  7. Edit the settings if desired by clicking on the Settings button.
  8. Adjust the Settings if desired.
     

1 If choosing US country defaults during the Affinity or Callisto software installation, the Directionality test will be available by default.

2 If selecting NO, you will have to create the protocol from scratch, which is beyond the scope of this document. For more info, please refer to the Instructions for Use document, Additional Info document or Quick Guide on Protocol Setup

December 2013

Balance

Vestibular Diagnosis and Treatment
A Physical Therapy Approach

 
Head roll to the right Head roll to the left

Helpful Hints 

  • Before performing any form of positioning maneuver, it is important to ascertain whether the patient has current or past injuries of the neck or spine
  • If neurological symptoms occur during the execution of positioning maneuvers, discontinue the procedure IMMEDIATELY and refer for a neurological evaluation. These symptoms might include: blurred vision, numbness, weakness of the arms or legs or confusion.
  • It is important to remember that the consistency of fluid inside the vestibular system is relatively viscous; therefore, you should allow sufficient time within each of the positions for the otoconia to achieve maximum displacement. This condition may also be responsible for a delayed onset of nystagmus.
  • It is most helpful to utilize Frenzel lenses or VNG when performing positional maneuvers. This reduces the ability of the patient to fixate during the procedure in an attempt to reduce the nystagmus response. This will also allow the examiner to see even very slight horizontal nystagmus.
  • It is common for the patient to tell you during the intake interview which ear is affected and will describe accurately the symptoms of BPPV. Use this information to determine which ear is likely the affected ear.
  • ALWAYS test both ears- even if the patient complains of only one side being affected
  • Patients are often very sensitive to horizontal canal BPPV, resulting in severe dizziness and vomiting. If the patient reacts violently during the roll test, immediately turn the patient to the opposite side and perform a Lempert 360° roll.

Procedure:

  • Begin with the patient sitting length-wise on the examination table
  • Place the Frenzel/VNG goggles on the patient
  • Guide the patient into a supine position. A slight elevation of the head (approximately 20°) is helpful
  • Have the patient turn his head 90° to either side. If the patient does not have enough cervical flexibility to provide maximum otoconia displacement, have the patient roll onto his shoulder.
  • Carefully observe whether nystagmus is present. Make note of the severity and the direction of the nystagmus.
  • Guide the patient back into a neutral, supine position
  • Turn the patient’s head 90° to the opposite side (roll onto the shoulder if necessary)
  • Again observe whether there is nystagmus; if so, make note of the severity and direction of the nystagmus
  • Guide the patient back into a neutral, supine position

Results:

  • Geotropic nystagmus - nystagmus is worse on the affected side and beats toward the ground. Best treated with the Lempert 360° roll. Acceptable alternative treatments are the Gufoni maneuver and forced prolonged positioning.
  • Apogeotropic nystagmus – nystagmus is worse on the unaffected side and beats away from the ground. Best treated by first converting the nystagmus to geotropic and then performing the Lempert 360° roll. Acceptable alternative treatments are head thrust, Gufoni maneuver, Vannucchi-Asprella and forced prolonged positioning.

References:
Korres S and others. Occurrence of semicircular canal involvement in Benign Paroxysmal Positional Vertigo. Otol Neurotol 23:926-932, 2002

Gans RE: Evaluating the Dizzy Patient: Establishing Clinical Pathways. Hearing Review 1999; 6 (6): 45-47

Fife TD. Recognition and management of horizontal canal benign positional vertigo. Am J Otol 1998;19:345-351

March 2017

Vestibular diagnosis and treatment 

Using EyeSeeCam vHIT to perform Suppression Head IMPulse test 

What is SHIMP
SHIMP stands for Suppression Head IMPulse test. It is used together with conventional Video Head Impulse Test (vHIT), also now referred to as the HIMP or Head IMPulse test. Used along with vHIT, it allows the clinician to determine the extent of vestibular function. In this quick guide we will use the abbreviations vHIT and SHIMP with the understanding that in the literature vHIT is now sometimes referred to as HIMP.

How is the test performed?
For SHIMP, the goggle is placed on the patient’s head in exactly the same way as it is positioned for vHIT. The eye should be centered in the viewing area to ensure that any reflections are beneath the pupil. After adjusting the goggle, centering the laser fixed dots on the wall, and calibrating the head and eye movements, you are ready to perform the SHIMP test. The laser dots will automatically enable when the SHIMP protocol is selected from the session menu.

SHIMPs are performed on the lateral canal by turning the head at least 7 times at high velocities to both the left and right sides. The patient should be instructed to fixate on the center dot generated by the head-fixed laser projected on the wall. The laser dot pattern is the same 5-dot pattern that is used for the calibration process (see the EyeSeeCam manual for details). The appearance of five dots instead of one is not a problem; just ask the patient to focus on the center dot. If you have a wall-fixed target already for vHIT you can begin by aligning the center laser-fixed dot on the same wall-fixed target that you use for the traditional head impulse test.

Starting Position using existing vHIT spot on the wall

  1. The first step is to have the patient relax his neck, open his eyes wide and fixate on the center dot in the 5-dot pattern.
  2. The second step is to turn the patient’s head either to the right or the left. The 5-dot laser pattern will move with the head so the dots are now located in a new position.
  3. The patient is instructed to keep his eyes on the center dot, so when the head moves the eyes should be focused on the newly positioned center dot.

Results
The VOR gains should be similar in vHIT and SHIMP tests. However, the pattern of saccades generated is different. vHIT rarely generates catch-up saccades in healthy patients, while in SHIMP testing, healthy subjects will make a large saccade at the end of the head turn (see figure below). This is referred to as a “SHIMP saccade”. This pattern of result is exactly opposite for impaired patients. An impaired VOR system will lead to a catch-up saccade on the vHIT but no (or very few) SHIMP saccades.

This is an example of healthy subject’s SHIMP results

This is the same patient with results in mirrored view.

When the VOR is impaired the eyes and the target move with the head during head impulses. Therefore, when the SHIMP test is performed on an impaired patient, the eyes always stay on the target, hence no need to make a catch-up saccade. On a healthy subject, when the head is turned (e.g., to the right) the VOR will drive the eyes in the opposite direction (e.g. to the left) and the patient will need to correct for the resulting offset in eye position by making a saccade back to the laser target, hence creating a SHIMP saccade. In an abnormal patient, e.g. someone with an acute unilateral vestibular neuritis, the patient will have no or very few SHIMP saccades for head turns toward the side of lesion.

Summary
Conventional Head Impulse Testing vHIT (or HIMP) is used clinically to identify a deficit in the VOR. When using an earth-fixed target, patients with vestibular losses cannot correct for the head movement so they lose fixation on the target, which results in the patient making a catch- up saccade to return to the target. A healthy person should not lose focus on the earth-fixed target because the VOR keeps the eyes on the target during the head movement. For vHIT, a saccade indicates an impaired vestibular system.

On the other hand, the SHIMP testing is used clinically to provide additional information regarding the VOR function. People with functioning vestibular systems must make a corrective saccade to follow a head-fixed target, while a person with a vestibular loss can follow the target without making a saccade because their eyes move with their head, hence they are always looking at the target. For SHIMPS, a saccade indicates a functioning vestibular system.

It is helpful to use both tests on each patient since they provide complementary results. For e.g. in cases where vHIT is hard to interpret alone (low gain) the SHIMP test can help in determining if the vestibular system is functioning. SHIMPs can also be used for corroborating the level of residual function to help realistic patient expectations before starting rehabilitation.

August 2017

What is a MMN/ P300/?

The mismatch negativity (MMN) response is a negative wave elicited in an ‘oddball’ paradigm where by a deviant stimuli is presented amongst a stream of repeated, or standard, stimuli. The response can be observed by subtracting the responses to the standard stimuli from those of the deviant, and it occurs in the latency region of around 100-300ms. See Fig1, showing an MMN from a 2 kHz deviant tone burst presented amongst a stream of 1 kHz standard tone bursts, measured between vertex and linked- mastoid positions.

Figure 1 MMN response

The P300 response is a positive wave that is also usually elicited in an oddball paradigm. Unlike the MMN, which can be measured without any task requirements, the P300 only occurs when the listener is actively attending to the stimuli. See Fig 2, showing a P300 from a 2 kHz deviant tone burst presented amongst a stream of 1 kHz standard tone bursts, measured between vertex and linked- mastoid positions.

Figure 2 P300 response

Why MMN/P300/?
The MMN and P300 can be used to evaluate higher level auditory function. The MMN test is particularly related to the brain’s ability to discriminate between speech sounds, and its independence of attention may make is suitable for use in evaluating auditory function in various populations in clinical neuroscience and in infants and newborns (Garrido et al., 2009).

How to test
Patient
Preparation is very important. Patient arousal and attention state greatly affects the amplitudes of the MMN response, so it is very important that the patient understands the test procedure. The MMN can also be elicited when the subject pays attention to stimuli, but it is difficult to measure in this condition because of the overlapping N2 component. As a result it is recommended to record the MMN while the subject ignores the stimuli. This can be done by letting the subject read or watch a silent captioned video during recording.

The MMN amplitudes decrease with various stages of sleep. It is not advised to perform MMN under sedation.

Electrode Placement:
It is possible to obtain P300/MMN with a standard 2-channel electrode montage, with an active vertex electrode referenced to either right or left mastoid. However, stronger responses can be obtained by linking the right and left mastoids, recording both from the ipsilateral and contralateral side in order to avoid a bias in hemispheric laterality.

Setting up the Eclipse
The Eclipse comes with a pre-programmed protocol for P300/MMN testing (license), ready for immediate use. Protocols can be created or modified easily to fit your clinic needs. Consult your Eclipse Additional Information to learn how to create or modify a protocol.

Protocol settings

  • P300/MMN should be measured using toneburst from 250 Hz-4 kHz and custom wave files at an intensity of a moderate levels.
  • Custom wavefiles inclusing Da, Ba and Ga are placed on the EPx5 CD-ROM. Please refer to the chapter Importing wavefiles for stimuli in Instruction for Use for guidelines on importing and calibrating custom wavefiles.

Summary of parameters for P300 and MMN

    P300 Response (deviant curve) MMN (subtracted curve frequent - deviant)
Subject State

Awake and quit adults, children and infants

Awake and quit adults, children and infants

Eyes Eyes open Eyes open
Condition Attend

Ignore conditions

Stimuli Types of stimuli

Tone burst, speech vowels or consonant vowel combinations

Tone burst, speech vowels or consonant vowel combinations

Inter-nset interval

0.1-1 sec

0.1-1 sec
Stimulus duration 

50-300ms

Be careful of overlapping response if analysis time is short

50-300ms

Be careful of overlapping response if analysis time is short

Presentation

Oddball paradigm
Deviant probability 0.05-0.20 Number of deviants at least 200

Oddball paradigm
Deviant probability 0.05-0.20 Number of deviants at least 200

Intensity

60-80dB peSPL

60-80dB peSPL

Recordings Reference electrode

Tip of nose of averaged reference (jumped electrodes)

Tip of nose of averaged reference (jumped electrodes)

Filtering

1-30Hz

1-30Hz
Analysis time

Pre stimuli -100ms
Post stimuli 700ms or more

Pre stimuli -100ms
Post stimuli 700ms or more
Sweep

50-300 (A total sweep of 2000, with 15% deviant stimuli gives 300 deviant sweeps.

50-300 (A total sweep of 2000, with 15% deviant stimuli gives 300 deviant sweeps.
Replications

At least 2, resulting in at least 200 deviants

At least 2, resulting in at least 200 deviants
Measurements 

Adult

Children

Infants

Measures

P1, N1, P2 & P3
P1, N200-250
Reliable components
Baseline to peak amplitude, peak latency

Use latency window established using grand mean data

N1, P2 & MMN

Any age, use difference waveform (response to deviant)

Baseline to peak amplitude, peak latency

Consider mean MMN amplitude in response window

Use latency window established using grand mean data

Response presence  Determined by

Replicable components

Response 2-3 times larger than amplitude in pre-stimulus interval

Replicable components

Response 2-3 times larger than amplitude in pre-stimulus interval

 


References
Garrido, M. I, Kilner, J.M, Stephan., K.E., and Friston, K.J. (2009) The mismatch negativity: A review of underlying mechanisms. Clinical Neurophysiology 120 453–463.

Hall, J.W. (2007). New Handbook of Auditory Evoked Responses. Pearson
Picton, T. (1992) The P300 wave of the human event-related potential. Journal of Clinical Neurophysiology 9 (4) 456-479.

July 2017

Vestibular Diagnosis and Treatment
Utilizing Rotary Chair

Purpose of Test:
The purpose of this test is to assess the patient’s Vestibulo-Ocular Reflex (VOR) by rotating the patient in a pendular pattern at various frequencies ranging from 0.01 Hz up to 0.64 Hz with vision denied. This test is considered the “gold standard” test for identifying a bilateral vestibular weakness. The SHA test can also be used to aid in the diagnosis of a unilateral vestibular loss, and can be used to monitor vestibular compensation over time.

Patient Instructions:
“You will feel yourself rocking back and forth slowly in the chair. During the rotation, I will be asking you several questions to keep you alert. Please keep your eyes open during the entire test.”

What to Expect:
A patient with normal SHA results will produce an eye position tracing that shows nystagmus changing from right-beating to left-beating as the chair changes directions. The plotted points in the eye velocity graph will appear to be approximately 180 degrees out of phase from the yellow chair signal trace. The resulting data points for each frequency tested will appear in the Gain, Phase, and Symmetry graphs on the summary screen. These data points will appear in the white region when results are normal and will appear in the shaded region when they are outside of threshold limits. The larger data point denotes which test frequency eye position and eye velocity graphs are currently being displayed. The first half- cycle of each frequency tested is excluded from analysis for improved reliability.

SHA test showing normal responses from 0.01 to 0.32 Hz

Abnormal Test Results:
Abnormal SHA test results may present in several different ways. Reduced VOR gain over a range of test frequencies may indicate that there is a bilaterally weak peripheral vestibular system, provided that technical issues have been accounted for. Please note that phase and symmetry values are of little diagnostic value in the case significantly reduced gains.

A higher than expected phase lead may provide evidence of a disorder affecting the peripheral vestibular system and/or vestibular nerve, or central pathology in rare cases. A decreased phase lead is more often related to central pathology, but may also be observed in the presence of vestibular migraines or motion intolerance.

An asymmetric response is similar to a directional preponderance in caloric testing. An asymmetric SHA response indicates that there is a difference between maximum left-beating and maximum right-beating eye velocity during sinusoidal rotation and provides evidence of a potential unilateral vestibular pathology.

SHA test showing significantly reduced VOR gain across all frequencies

SHA test showing borderline reduced phase across all frequencies

Spectral Purity
In addition to Gain, Phase, and Symmetry, an additional parameter, Spectral Purity, is available in SHA testing. A high percentage of Spectral Purity indicates a more reliable result. The closer the data fits a sine wave, the higher the spectral purity. When spectral purity falls below 60%, it provides evidence that the response may not be of high quality and the clinician should consider retesting that frequency.

SHA test showing poor spectral purity at 0.32 Hz, resulting in erroneous data at that frequency

Conclusion:
SHA testing can be used to identify a bilateral weakness or aid in diagnosis of a unilateral weakness, and allows the clinician to see how the patient’s VOR is performing across multiple frequencies over time. It is a very sensitive test, but is not necessarily a specific test. Therefore, in order to get a more comprehensive look at the vestibular system (lateral semicircular canals), a clinician may choose to perform video head impulse testing (vHIT) or caloric testing along with rotational chair testing.

Note: This is intended only as a guide, official diagnosis should be deferred to the patient’s physician.


References
Jacobson, GP, and Shepard, NT. Balance Functional Assessment and Management, 2nd Ed. San Diego; Plural Publishing, 2015.

March 2017

Vestibular Diagnosis and Treatment
Utilizing Videonystagmography (VNG)

Purpose of Test:
The purpose of caloric irrigation is to identify the degree to which the vestibular system is responsive and also to determine how symmetric the responses are, between left and right. It is a test of the lateral semicircular canals alone -- it does not assess vertical canal function or otolithic function. By using caloric irrigation, you are stimulating each end organ independently of the other to determine whether one end organ is weaker than the other (asymmetry) or whether neither end organ is providing sufficient vestibular information to the brain.

Considerations:

  • Pre-test instructions/medications – There is conflicting literature on whether patients should be asked to discontinue central nervous system suppressant medications for 48 hours prior to the VNG. Part of this debate is that patients often don’t understand which medications are allowed and which are not allowed. A general rule of thumb is that the patient should stop taking medications that are prescribed for “dizziness”, but continue to take other medications (such as heart medications, blood pressure medications, etc…).
  • A thorough examination of the external ear canal and tympanic membrane is necessary prior to irrigation. The three most important factors to consider are the presence of cerumen, the presence of a tympanic membrane perforation, and the shape of the ear canal. If excessive cerumen is present, it might preclude the stimulus from reaching the inner-most portion of the ear canal and could therefore prohibit a reliable test result. Removal of even the smallest amounts of cerumen is beneficial to the testing process. In the presence of a TM perforation, caloric stimulation by water cannot be completed. Stimulation by air can be performed only briefly to determine whether or a not a vestibular response is present; however, accurate unilateral weakness and directional preponderance measures cannot be calculated. Examination of the shape and curvature of the ear canal is essential to reliable test results for two reasons: (1) Because the irrigator tip is straight and ear canals rarely are, it is not uncommon for the insertion of the irrigator tip to cause slight discomfort to the patient (2) It is important for the stream of air/water from the irrigator to be directed near, but not directly on, the tympanic membrane to avoid injury to the patient. Without a thorough examination of the ear canal, it is impossible to know whether the achieved test results are an accurate assessment of the vestibular system.
  • It is necessary to perform VNG with the patient in a vision-denied state to disallow fixation suppression of the nystagmus response
  • Alerting tasks are also necessary to discourage the patient from suppressing the nystagmus. The most effective alerting tasks require the patient to use recall memory – i.e. “name a state that begins with the letter ____…” ,“name a color that begins with ___”, “name a city in the state of ________”, etc…
  • It is suggested that you begin with warm irrigations (which provide an excitatory response) if for no other reason than if the patient cannot tolerate bi-thermal irrigation, the examiner has AT LEAST enough information to provide a score for the Monothermal Warm Screening Test (MWST).
  • MWST is a screening test used mainly for patients who cannot tolerate bi-thermal testing. It is a percentage of asymmetry derived from only the warm-caloric irrigation responses.
  • You should wait between 3 and 5 minutes between irrigations, as the nystagmus from the previous test must be completely resolved before you perform the next irrigation. It is suggested that you look at the eyes during the rest periods to watch the nystagmus dissipate. Removal of the mask cover during these rest periods can be helpful to allow the patient to suppress any residual response.
  • A “fixation period” of 10 seconds is recommended as a diagnostic tool during the recording of the caloric response (at approximately 90 seconds after the onset of irrigation). The inability to suppress nystagmus when a fixation target is provided is considered a pathological indication of central vestibular pathology.

Patient Instructions:
“I am going to put warm and cool air/water into each ear. I will begin by putting warm air in the right/left ear. The air/water will sound loud and will feel warm, but it should not be painful. If you experience pain, please tell me immediately. The air/water will be in your ear for approximately 60 seconds (30 for water). After 60 (30) seconds, I will take the air/water out of your ear and I will begin to ask you questions. I need two things from you: to keep your eyes open AT ALL TIMES – even if you are feeling “like you are in motion” - and focus on the questions that I am asking you to answer. Do you have any questions before we begin?” It is also helpful to reassure the patient that the sensation of motion is to be expected and will not last very long.

What to Expect:
A fully functional peripheral vestibular end organ will begin to respond to stimulation approximately 15-30 seconds into the irrigation procedure and will reach its peak approximately 60-90 seconds from the beginning of the irrigation process (air stimulus is used in the examples shown here). A rule of thumb is that warm air/water will produce nystagmus that beats toward the test ear and cool air/water will produce nystagmus that beats away from the test ear. (COWS – Cold Opposite, Warm Same). The nystagmus beats are represented by the dots plotted on the graph for each condition. The yellow bar represents the area of maximum performance. Each condition is giving a maximum Slow Phase Velocity (SPV) value and a Fixation Index value (FI). All 4 SPV values are added and a total SPV values is also displayed. The SPV values are used to calculate the overall weakness and to determine if any directional preponderance is present.

COMMON NORMATIVE VALUES FOR CALORIC RESPONSE PARAMETERS

 PARAMETER:

 LABELED AS:

 COMMON NORM:

 Unilateral Weakness

UW%

 <25%

 Directional Preponderance

DP%

 <30%

 Fixation Suppression

FI%

 <50%

 Bilateral Weakness

Each ear total >11deg/sec

 

 Hyperactivity

Each ear total >140deg/sec

 

Threshold values for caloric testing, as referenced from Jacobson, GP, and Shepard, NT. Balance Functional Assessment and Management, 2nd Ed. San Diego; Plural Publishing, 2015

Caloric test showing normal response

Abnormal Test Results:
Abnormal caloric test results can present in several ways: as an asymmetry between ears (labeled as “unilateral weakness”), as “directional preponderance” (“directional preponderance” numerically expresses how the amount of right-beating nystagmus compares with the amount of left-beating nystagmus) or as a display of symmetrical, but weak, responses from both ears (labeled as “bilateral weakness”).


Caloric test showing a unilateral weakness (UW)


Caloric test showing a UW, a directional preponderance (DP), and an abnormal fixation value for L44⁰C


Caloric test showing a bilateral weakness (Please note: UW and DP will not be calculated when results present as a bilateral weakness)

Conclusion:
Caloric irrigation is the most valuable tool available to the healthcare field with which to assess vestibular function. It is the only test that allows for evaluation of each peripheral vestibular end organ independently of the other. Caloric irrigation gives the healthcare professional an assessment of whether the peripheral vestibular end organs are functioning symmetrically and/or whether the peripheral vestibular end organs are providing the brain with sufficient sensory information.

For a complete discussion of differential diagnosis using caloric irrigation in VNG, refer to: 

Jacobson, GP, and Shepard, NT. Balance Functional Assessment and Management, 2nd Ed. San Diego; Plural Publishing, 2015

Note: This is intended only as a guide, official diagnosis should be deferred to the patient’s physician.

March 2017

Vestibular Diagnosis and Treatment
Utilizing Rotary Chair

Purpose of Test:
To assess the patient’s ability to suppress the Vestibulo-Ocular Reflex (VOR) while rotating. The patient is rotated in a pendular pattern at various frequencies ranging from 0.04 Hz up to 0.32 Hz while focusing on a fixation light within the enclosed goggles. By comparing the patient’s vision-denied SHA results to the VOR suppression results at the same frequency of rotation, a percentage of gain reduction can be calculated.

Patient Instructions:
“You will feel yourself rocking back and forth slowly in the chair. During the rotation, you will see a small green light appear within the mask (sometimes you may see more than one light, that is ok, just choose one light and focus on it). Please keep your eyes open and focused on the green light during the entire test. Try to prevent the light from ‘bouncing’ around in your view.”

What to Expect:
A patient with normal VOR suppression results will produce a tracing that shows significantly reduced nystagmus as the patient is rotated sinusoidally from left to right in the chair. The data points for each frequency tested will appear as triangles in the Gain (%) and Reduction (%) graphs above the eye position (°) and eye velocity (°/s) graphs on the summary screen.. The circular data points represent the previously recorded SHA results at the same frequency of rotation. The green data point denotes which frequency tracing is currently being displayed. Triangles that appear in the white region in the Reduction (%) graph represent a normal response. Triangles that appear in the shaded region indicate that the data falls outside of threshold limits. The first half-cycle of each frequency tested is excluded from analysis for improved reliability.

VOR Suppression test showing a normal response

Abnormal Test Results:
A failure to sufficiently suppress the VOR can be an indicator of possible central pathology.

VOR Suppression test showing an abnormal reduction percentage at 0.32 Hz

Conclusion:
VOR Suppression testing can be used to test the central vestibular pathways and allows the clinician to see the patient’s VOR suppression performance across multiple Sinusoidal Harmonic Acceleration frequencies, typically above 0.04 Hz.

Note: This is intended only as a guide, official diagnosis should be deferred to the patient’s physician.


References 
Jacobson, GP, and Shepard, NT. Balance Functional Assessment and Management, 2nd Ed. San Diego; Plural Publishing, 2015

March 2017

Vestibular Diagnosis and Treatment
A Physical Therapy Approach

Treatment of the left horizontal canal:

Roll the patient's body toward the unaffected side. Roll the patient into the prone position.
Roll the patient's body toward the affected side.

Helpful Hints:

  • Utilizing Video Frenzel or VNG while performing this maneuver is recommended to reduce the ability of the patient to fixate during the procedure in an attempt to reduce the nystagmus response. This will also allow the examiner to see even very slight horizontal nystagmus. If the treatment is successful, the nystagmus will beat in the same direction throughout the procedure.
  • The success rate of this procedure in the treatment of horizontal canal BPPV is very high and success is usually immediate. If the procedure is successful, the patient may not exhibit symptoms during the last steps of the procedure.
  • If the patient does not show marked improvement upon completion of the procedure, you should repeat the procedure. If there is still no improvement, it is possible that the wrong ear has been treated.
  • It is important that the patient maintain the 20° head position to prevent the otoconia from reversing direction within the horizontal canal during the procedure
  • Refer to attached chart for specific details regarding diagnosis and treatment of each nystagmus condition
  • The patient’s compliant will often be that he/she experiences “dizziness” when turning his/her head in bed without turning the body

Procedure:

  • Begin by having the patient lay in supine position with the head elevated at approximately 20o
  • Roll the patient onto the shoulder of the unaffected side
  • Hold this position for 30-60 seconds
  • Roll the patient into the prone position maintaining the 20° head position (this will require the patient to hang their head off the table as illustrated)
  • Hold this position for 30-60 seconds
  • Next, roll the patient onto their affected side while maintaining the 20° head position
  • Hold this position for 30-60 seconds
  • Guide the patient back into a sitting position

Right Geotropic Horizontal Canal BPPV
SYMPTOM: Nystagmus is greater when affected (right) ear is in the downward position
TREATMENT: Lempert 360° roll to the LEFT
NYSTAGMUS: Should beat toward the LEFT throughout the entire procedure
IMPLICATION: Pathological localization is generally in the utricle of the affected ear

Left Geotropic Horizontal Canal BPPV
SYMPTOM: Nystagmus is greater when affected (left) ear is in the downward position
TREATMENT: Lempert 360° roll to the RIGHT
NYSTAGMUS: Should beat toward the RIGHT throughout the entire procedure
IMPLICATION: Pathological localization is likely in the utricle of the affected ear

Right Apogeotropic Horizontal Canal BPPV
SYMPTOM: Nystagmus is greater when affected (right) ear is in the upward position
TREATMENT: Convert nystagmus from apogeotropic to geotropic by using one of the methods listed below
IMPLICATION: Pathological localization is likely in the horizontal canal of the affected ear

Left Apogeotropic Horizontal Canal BPPV
SYMPTOM: Nystagmus is greater when affected (left) ear is in the upward position
TREATMENT: Convert nystagmus from apogeotropic to geotropic by using one of the methods listed below
IMPLICATION: Pathological localization is likely in the horizontal canal of the affected ear

Conversion Methods for Apogeotropic Horizontal Canal BPPV

  • Head Thrust
  • Modified Guffoni
  • Vannucchi -Asprella
  • Forced Prolonged Positioning

References:
Lempert T, Tiel-Wilck K. A positional maneuver for treatment of horizontal canal benign positional vertigo. Laryngoscope 1996;106:476-478

Fife TD. Recognition and management of horizontal canal benign positional vertigo. Am J Otol. 1998;19(3):345-351

Tirelli G, Russolo M. 360-Degree canalith repositioning procedure for the horizontal canal. Otolaryngol Head Neck Surg. 2004 Nov;131(5):740-6 

March 2017

Vestibular Diagnosis and Treatment
A Physical Therapy Approach

Start with patient sitting up.

Rapidly move to a Side-lying position.

Quickly position head at a 45 degree angle with nose
pointing down.

Helpful Hints:

  • Before performing any form of positioning maneuver, it is important to ascertain whether the patient has current or past injuries of the neck or spine
  • If any neurological symptoms occur during the execution of positioning maneuvers, discontinue the procedure IMMEDIATELY and refer for neurological evaluation. These symptoms might include: blurred vision, numbness, weakness of the arms or legs or confusion.
  • This procedure is an alternative treatment for patients who cannot complete the Lempert 360o Roll, as well as for cases where an apogeotropic lateral canal variant may be present

Procedure:

  • Begin with the patient sitting on the edge of the examination table, facing the examiner
  • With a rapid motion, guide the patient into a side-lying position toward the affected side
  • While the patient is lying on his side, with a quick movement, turn the patient’s head to a 45o angle (so that the patient’s nose is pointing toward the table)
  • Hold this position for 2-3 minutes
  • Guide the patient back into a sitting position

References:
Gufoni M, Mastrosimone I, DiNasso F. Repositioning maneuver in benign paroxysmal positional vertigo of the horizontal semicircular canal. Acta Otorhinolaryngol Ital 1998;18:363-7

Appiani GC, Catania G, Gagliardi M. A liberatory maneuver for the treatment of horizontal canal paroxysmal positional vertigo. Otology and Neurology 22:66-69, 2001

Hughes CA, Proctor L. Benign paroxysmal positional vertigo. Laryngoscope. 1997;107:607-613.

March 2017

Vestibular Diagnosis and Treatment
A Physical Therapy Approach

Treatment of the left anterior canal:

Turn the head 45° to the left side. Rapidly move into side-lying position on the affected side.  Rapidly move to patients unaffected side with the nose 45° upward.

Helpful Hints:

  • Before performing any form of positioning maneuver, it is important to ascertain whether the patient has current or past injuries of the neck or spine
  • If any neurological symptoms occur during the execution of positioning maneuvers, discontinue the procedure IMMEDIATELY and refer for a neurological evaluation. These symptoms might include: blurred vision, numbness, weakness of the arms or legs or confusion.
  • The patient should experience vertigo when moved to the face-down position. If not, it is often useful to perform a slight headshake in an effort to loosen otolithic debris.

Procedure:

  • Begin with the patient sitting on the examination table, facing the examiner, with the patient’s head turned toward the affected side at a 45° angle
  • Guide the patient into a side-lying position on the affected side. (This should be a rapid movement and the patient’s nose should be pointing downward.)
  • Hold this position for 2-3 minutes
  • While maintaining the 45o head position, guide the patient in a continuous motion from side-lying on the affected side to side-lying on the unaffected side. (The patient’s nose should be pointing upward.)
  • Hold this position for 3-5 minutes
  • Guide the patient back into a sitting position

References:
Semont, Freyss G, Vitte E. Curing the BPPV with a liberative maneuver. Adv Otorhinolaryngol. 1998;42:290-3

Hughes CA, Proctor L. Benign paroxysmal positional vertigo. Laryngoscope. 1997;107:607-613

March 2017

Vestibular Diagnosis and Treatment
Utilizing Rotary Chair

Purpose of Test:
The purpose of Step Test is to assess the patient’s Vestibulo-Ocular Reflex (VOR) by rotating the patient at an acceleration impulse of 100°/s2 to a fixed chair velocity with vision denied. The time constants, response gain, and time constant asymmetry are then measured. By measuring the vestibular system time constant, both the peripheral vestibular response to the rotational stimulus, as well as the central velocity storage mechanism can be evaluated, making this a useful test for aiding in the diagnosis of a variety of vestibular disorders.

Patient Instructions:
“You will feel yourself rotating in one direction for several seconds. During the rotation, I will be asking you several questions to keep you alert. As you are rotating, you may feel as though you are slowing down. When the chair stops, you will feel as though you are rotating in the opposite direction. There will be four segments and each segment will take approximately 1 minute. Please keep your eyes open during the entire test.”

What to Expect:
A patient with normal Step Test results will produce a tracing that demonstrates robust nystagmus at the beginning of each per-rotary and post-rotary step. The nystagmus will then decay over time as the patient perceives that the chair is slowing down or even stopping. The nystagmus points will be marked with triangles in the eye position (°) graph, and the corresponding eye velocity (°/sec) graph displays data points representing each detected beat. The vertical dashed lines in the eye velocity graph represent the start and end points for the time constant measurement and the curve fit is displayed in yellow. The data points for each per-rotary and post-rotary step at each velocity tested will appear as triangles in the gain (%), time constant (s), and time constant symmetry (%) graphs above the tracings on the summary screen.. These data points will appear in the white region when results are normal and will appear in the shaded region when results are outside of threshold limits.

Step test showing a normal response

Abnormal Test Results:
An abnormal Step test may present in many different ways. The most diagnostically significant parameter in Step test is the time constant, which is the amount of time it takes for the slow phase velocity of the nystagmus to decrease by 37% of its peak velocity. Reduced time constants may be associated with unilateral or bilateral vestibular pathology, or central vestibular involvement. It has been suggested that abnormally long time constants may be associated with motion intolerance or central vestibular pathology. Abnormalities in time constant symmetry can be useful in helping to determine the weaker side in unilateral vestibular pathology, particularly with the higher velocity step test.

Step test showing reduced gain and time constants

Conclusion:
Step testing, along with SHA and VOR Suppression tests, can be useful in identifying a unilateral or bilateral vestibular pathology, and can help differentiate between peripheral and central involvement. In order to obtain a more compressive evaluation of the vestibular system (lateral semicircular canals), a clinician may choose to perform video head impulse testing (vHIT) or caloric testing, along with rotational chair testing.

Note: This is intended only as a guide, official diagnosis should be deferred to the patient’s physician.


References 
Jacobson, GP, and Shepard, NT. Balance Functional Assessment and Management, 2nd Ed. San Diego; Plural Publishing, 2015.

March 2017

Vestibular Diagnosis and Treatment
Utilizing Videonystagmography (VNG)

Purpose of Test:
To assess the patient’s ability to maintain a steady gaze on an object at various angles without the eye generating extraneous movements (i.e. square wave jerks or nystagmus). The inability to maintain a steady gaze is an indication of either a central or peripheral vestibular system lesion. Gaze positions tested are: center (straight ahead), gaze left, gaze right, gaze up and gaze down.

Patient Instructions:
“You will see a green dot on the screen. Simply look at the dot. If the dot moves, follow it with your eyes only. Try not to move your head.”

What to Expect:
A patient with normal gaze ability will produce a tracing that is virtually a straight line once the eyes are fixated on the target. The right eye is represented by the red line and the left eye by the blue line. If nystagmus is present it will be identified by triangles on the eye position graph to represent each detected nystagmus beat. The average slow phase velocity value(s) will be plotted in the bar graphs to the right of the tracings. When the average slow phase velocity exceeds the threshold value of 6⁰/sec, the bar graph will be shaded grey and a red diamond will appear near the bar graph to indicate an out of threshold response.

Gaze test showing normal response for all gaze angles (center, left, right, up and down)

Abnormal Test Results:
An “abnormal” gaze tracing might present itself in several ways. A patient may present with square wave jerks, nystagmus, or gaze decay. Below are examples of abnormal tracings:

Gaze test showing bilateral gaze-evoked nystagmus

Gaze test showing down-beating nystagmus on gaze down 20⁰

Conclusion:
Gaze testing is the ONLY test of the four ocular tests in which an “abnormal” result could be generated either from the peripheral vestibular system or from the central vestibular system.

For a complete discussion of differential diagnosis using the gaze stability test, refer to: 

Jacobson, GP, and Shepard, NT. Balance Functional Assessment and Management, 2nd Ed. San Diego; Plural Publishing, 2015

Note: This is intended only as a guide, official diagnosis should be deferred to the patient’s physician.

March 2017

Vestibular Diagnosis and Treatment
A Physical Therapy Approach

Dix-Hallpike test performed to the right:

Begin with patient seated, wearing goggles, with head turned 45° to the right

Quickly lie the patient back with head turned 45° and hanging approximately 20°

Dix-Hallpike test performed to the left:

Begin with patient seated, wearing goggles, with head turned 45° to the left

Quickly lie the patient back with head turned 45° and hanging approximately 20°

Precautions:

  • Before performing any positioning maneuver, it is important to ascertain whether the patient has current or past injuries of the neck or spine
  • If neurological symptoms occur during the execution of positioning maneuvers, discontinue the procedure IMMEDIATELY and refer for a neurological evaluation. These symptoms might include: blurred vision, numbness, weakness of the arms or legs or confusion.
  • It is important to remember that the consistency of fluid inside the vestibular system is relatively viscous; therefore, you should allow sufficient time within each of the Dix-Hallpike maneuvers for the otoconia to achieve maximum displacement. This condition may also be responsible for a delayed onset of nystagmus.
  • It is most helpful to utilize Frenzel lenses or VNG while performing the Dix-Hallpike test. This reduces the ability of the patient to fixate during the procedure in an attempt to reduce the nystagmus response. This will also allow the examiner to see even very slight torsional nystagmus.
  • It is not unusual for the patient to lose postural control at the completion of the procedure due to the otoconia briskly falling within the cupula. It is vital that the examiner is in a stance that will provide the patient with postural support in this situation.
  • It is common for the patient to tell you during the intake interview which ear is affected and to describe accurately the symptoms of BPPV. Use this information to determine which ear is likely the affected ear.
  • ALWAYS test both ears- even if the patient complains of only one side being affected

Procedure

  • Begin with the patient sitting length-wise on the examination table
  • Place the Frenzel/VNG goggles on the patient
  • Have the patient turn his head to a 45° angle toward the side that you suspect to be affected (the affected side)
  • While maintaining the 45° head position, guide the patient in a continuous motion from sitting to lying with the head hanging off the table at approximately 20°. IT IS IMPERATIVE TO PROVIDE CERVIAL SUPPORT DURING THIS PORTION OF THE PROCEDURE.
  • Hold this position for 30-60 seconds or until nystagmus has subsided
  • Guide the patient back into a sitting position
  • Allow 30-60 seconds in the sitting position to allow for the patient to recover
  • Have the patient turn his head 90° toward the unaffected side, so that the head is at a 45° angle toward the unaffected side
  • While maintaining the 45° head position, guide the patient in a continuous motion from sitting to lying with the head hanging off the table at approximately 20°. IT IS IMPERATIVE TO PROVIDE CERVIAL SUPPORT DURING THIS PORTION OF THE PROCEDURE.
  • Hold this position for 30-60 seconds or until nystagmus has subsided
  • Guide the patient back into a sitting position
  • Maintain postural support until the patient is physically stable

References:

  • Dix MR, Hallpike CS.Pathology ,symptoms and diagnosis of certain disorders of the vestibular system. Proc R Soc Med. 1952;45:341-354
  • Hughes CA, Proctor L. Benign paroxysmal positional vertigo. Laryngoscope. 1997;107:607-613.

Dix-Hallpike - Test for Diagnosis of BPPV

Posterior Canalithiasis

  • Perception of vertigo often occurs in conjunction with the nystagmus
  • Evidenced by an upbeat, torsional nystagmus (torsion toward the affected side)
  • Recommended treatment is the Epley Maneuver of the affected side
  • Alternative treatments might include the Semont Liberatory Maneuver or Brandt-Daroff Exercises

Posterior Cupulothiasis

  • Perception of vertigo may subside even though nystagmus is still present
  • Evidenced by an upbeat, torsional nystagmus (torsion toward the affected side)
  • Recommended treatment is the Semont Liberatory Maneuver
  • An alternative treatment is Brandt-Daroff Exercises

Anterior Canalathiasis

  • Perception of vertigo often occurs in conjunction with the nystagmus
  • Evidenced by a downbeat, torsional nystagmus (torsion toward the affected side)
  • Recommended treatment is the Epley CRP
  • Alternative treatments might include the Semont Liberatory Maneuver or Brandt-Daroff Exercises

Anterior Cupulothiasis

  • Perception of vertigo may subside even though nystagmus is still present
  • Evidenced by a downbeat, torsional nystagmus (torsion toward the affected side)
  • Recommended treatment is the Semont Liberatory Maneuver
  • An alternative treatment is Brandt-Daroff Exercises
March 2017

Vestibular Diagnosis and Treatment

Utilizing Video Head Impulse test (vHIT)

Purpose of test: 
To assess the patient’s vestibulo-ocular reflex (VOR) for the Left Anterior and Right Posterior (RALP) semicircular canals. The test allows you to view head and eye movement tracings simultaneously in real time. VOR instantaneous gain and velocity regression are calculated for both Left Anterior and Right Posterior canals during this test.

Calibration:
Two calibrations will be completed prior to beginning the test. Standard calibration is completed to calibrate the patient’s eye relative to the laser targets. Place the patient 1.5 meters from the wall on which the laser targets will be projected. Once standard calibration is started, the patient will see 5 red laser dots appear. Instruct the patient to keep his/her head still while moving their eyes between the dots as instructed. Head calibration is completed to calibrate the Inertial Measurement Unit (IMU). With the patient’s eyes fixated on a single target, instruct him/her to gently move the head side to side approximately 5° from center in either direction for 5 seconds. Next, have the patient move the head up and down, following the same procedure.

 

Beginning the Test:
To begin a LARP test, select LARP from the session menu, click prepare, then start. The impulses will be performed while standing behind the patient with your hands placed on top of the patient’s head. You will be testing in the plane of Left Anterior/Right Posterior canals, as shown below.

Patient Instructions:
“I will be moving your head up and down in an angular pattern. Keep your eyes focused on the target on the wall the entire time. Please do not try to resist the head movements, as this will negatively impact the test results. Simply keep your neck loose to allow me to make the small movements.”

Impulse Guides:
A guide is present on the test screen to help you generate LARP impulses of appropriate acceleration and velocity. A green check mark, along with an audible ding, indicates that the impulse was successfully completed and met the criteria to be included in the final report. A red “x” along with audible dong indicates that the impulse did not meet the criteria and will not be allowed into the final report. The counter next to test name allows you to view how many accepted impulses have been collected.

In addition, a head detection guide and 3D head model allows you to see whether or not you are moving the patient’s head in the right plane for a LARP test.

LARP head detection guides

LARP head detection guides

What to Expect:
A patient with normal Left Anterior/Right Posterior SSC function will produce eye tracings relative to head tracings that are essentially 180° out of phase, resulting in VOR gain that is near 1.0 for each of the SCCs tested. Velocity regression should show little to no asymmetry between the two canals tested. There will be no catch-up saccades present in the tracing, as the patient was able to keep their eyes fixated on the target during the LARP impulses.

LARP test showing normal test result

Normal LARP Result

Abnormal Test Results:
An “abnormal” LARP result will show reduced gain in one or both of the canals tested. Because the patient was not able to keep his/her eyes fixated on the target during impulses, he/she must produce a “catch-up” saccade to bring the eyes back to the target. Below are examples of “abnormal” LARP tracings:

LARP test showing abnormal test resultLARP test showing Right Posterior SCC gain reduction with the presence of covert catch-up saccades in a patient with right-side vestibular neuritis.

Conclusion:
LARP vHIT test can be used by the clinician to help determine the presence of Left Anterior/Right Posterior Semicircular Canal dysfunction. LARP vHIT testing should not be relied upon by itself, but rather should be used in conjunction with RALP and Lateral SSC tests, as well as other vestibular tests to diagnose the patient.

Note: This is intended only as a guide, official diagnosis should be deferred to the patient’s physician.

December 2016

Vestibular Diagnosis and Treatment

Utilizing Video Head Impulse test (vHIT)

Purpose of test:
To assess the patient’s vestibulo-ocular reflex (VOR) for the Right Anterior and Left Posterior (RALP) semicircular canals. The test allows you to view head and eye movement tracings simultaneously in real time. VOR instantaneous gain and velocity regression are calculated for both Right Anterior and Left Posterior canals during this test.

Calibration
Two calibrations will be completed prior to beginning the test. Standard calibration is completed to calibrate the patient’s eye relative to the laser targets. Place the patient 1.5 meters from the wall on which the laser targets will be projected. Once standard calibration is started, the patient will see 5 red laser dots appear. Instruct the patient to keep his/her head still while moving their eyes between the dots as instructed. Head calibration is completed to calibrate the Inertial Measurement Unit (IMU). With the patient’s eyes fixated on a single target, instruct him/her to gently move the head side to side approximately 5° from center in either direction for 5 seconds. Next, have the patient move the head up and down, following the same procedure.

Beginning the Test:
To begin a RALP test, select RALP from the session menu, click prepare, then start. The impulses will be performed while standing behind the patient with your hands placed on top of the patient’s head. You will be testing in the plane of Right Anterior/Left Posterior canals, as shown below.

Right Anterior Left Posterior

Patient Instructions:
“I will be moving your head up and down in an angular pattern. Keep your eyes focused on the target on the wall the entire time. Please do not try to resist the head movements, as this will negatively impact the test results. Simply keep your neck loose to allow me to make the small movements.”

Impulse Guide:
A guide is present on the test screen to help you generate RALP impulses of appropriate acceleration and velocity. A green check mark, along with an audible ding, indicates that the impulse was successfully completed and met the criteria to be included in the final report. A red “x” along with audible dong indicates that the impulse did not meet the criteria. The counter next to the test name allows you to view how many accepted impulses have been collected.

In addition, a head detection guide and 3D head model allows you to see whether or not you are moving the patient’s head in the right plane for a RALP test.

RALP head detection guides

What to Expect:
A patient with normal Right Anterior/Left Anterior SSC function will produce eye tracings relative to head tracings that are essentially 180° out of phase, resulting in VOR gain that is near 1.0 for each of the canals tested. Velocity regression should show little to no asymmetry between the two canals tested. There will be no catch-up saccades present in the tracing, as the patient was able to keep his/her eyes fixated on the target during the RALP impulses.

Normal RALP result

Abnormal Test Results:
An “abnormal” RALP result will show reduced gain in one or both of the canals tested. Because the patient was not able to keep his/her eyes fixated on the target during impulses, he/she must produce a “catch-up” saccade to bring the eyes back to the target. Below are examples of “abnormal” RALP tracings:

RALP test showing significantly reduced gain for Left Posterior SSC, with the presence of both covert and overt catch-up saccades.

Conclusion:
RALP vHIT test can be used by the clinician to help determine the presence of Right Anterior/Left Anterior Semicircular Canal dysfunction. RALP vHIT testing should not be relied upon by itself, but rather should be used in conjunction with LARP and Lateral SSC tests, as well as other vestibular tests to diagnose the patient.

Note: This is intended only as a guide, official diagnosis should be deferred to the patient’s physician.

December 2016

Vestibular Diagnosis and Treatment

Utilizing Video Head Impulse test (vHIT)

Purpose of test:
To assess the patient’s vestibulo-ocular reflex (VOR) for the Left and Right Lateral Semicircular Canals (SCC). The test allows you to view head and eye movement tracings simultaneously in real time. VOR instantaneous gain and velocity regression are calculated for both Left Lateral and Right Lateral canals during this test.

Calibration:
Two calibrations will be completed prior to beginning the test. Standard calibration is completed to calibrate the patient’s eye relative to the laser targets. Place the patient 1.5 meters from the wall on which the laser targets will be projected. Once standard calibration is started, the patient will see 5 red laser dots appear. Instruct the patient to keep his/her head still while moving their eyes between the dots as instructed. Head calibration is completed to calibrate the Inertial Measurement Unit (IMU). With the patient’s eyes fixated on a single target, instruct him/her to gently move the head side to side approximately 5° from center in either direction for 5 seconds. Next, have the patient move the head up and down, following the same procedure.

Beginning the Test:
To begin a lateral vHIT test, select lateral from the session menu, click prepare, then start. The impulses will be performed while standing behind the patient with your hands placed beneath the goggle strap around the patient’s jaw. You will be testing in the plane of Left Lateral/Right Lateral canals, as shown below.

Patient Instructions:
“I will be moving your head side to side in small movements. Keep your eyes focused on the target on the wall the entire time. Please do not try to resist the head movements, as this will negatively impact the test results. Simply keep your neck loose to allow me to perform the small movements.”

Impulse Guide:
A guide is present on the test screen to help you generate lateral impulses of appropriate acceleration and velocity. A green check mark indicates that the impulse was successfully completed and met the criteria to be included in the final report. A red “x” indicates that the impulse did not meet the criteria and will not be allowed into the final report. The counter next to test name allows you to view how many accepted impulses have been collected.

What to Expect:
A patient with normal Left and Right SSC function will produce eye tracings relative to head tracings that are essentially 180° out of phase, resulting in VOR gain that is near 1.0 for each of the SCCs tested. Velocity regression should show little to no asymmetry between the two canals tested. There will be no catch-up saccades present in the tracing, as the patient was able to keep their eyes fixated on the target during the lateral impulses.

Normal Lateral Test Result

Abnormal Test Results:
An “abnormal” lateral result will show reduced gain in one or both of the canals tested. Because the patient was not able to keep his/her eyes fixated on the target during impulses, he/she must produce a “catch-up” saccade to bring the eyes back to the target. Below are examples of “abnormal” lateral vHIT tracings:

Lateral vHIT test showing a Left Lateral Canal weakness in an acute stage of neuritis

Lateral vHIT test showing a bilateral asymmetrical lateral canal weakness in a cochlear impatient patient

Conclusion:
Lateral vHIT test can be used by the clinician to help determine the presence of Left/Right Semicircular Canal dysfunction. Lateral vHIT testing should not be relied upon by itself, but rather should be used in conjunction with RALP and LARPl SSC tests, as well as other vestibular tests to diagnose the patient.

Note: This is intended only as a guide, official diagnosis should be deferred to the patient’s physician.

December 2016

Vestibular Diagnosis and Treatment
A Physical Therapy Approach

Epley Maneuver for right posterior canal BPPV: 

Begin with the patient’s head turned 45 degrees toward the affected side.

Bring to a supine position with the head turned toward the affected side and hanging 20°.

Rotate the patient’s head 90 degrees toward the unaffected side.

Guide the patient to the side lying position with their nose pointing to the ground.

While keeping the head in 45°, tucked position,
return the patient to a seated position.

Helpful Hints:

  • It is most helpful to utilize Frenzel lenses or VNG while performing CRP. This reduces the ability of the patient to fixate during the procedure in an attempt to reduce the nystagmus response. This will also allow the examiner to see even very slight torsional nystagmus.
  • Before performing any positioning maneuver, it is important to ascertain whether the patient has current or past injuries of the neck or spine
  • If neurological symptoms occur during the execution of positioning maneuvers, discontinue the procedure IMMEDIATELY and refer for a neurological evaluation. These symptoms might include: blurred vision, numbness, weakness of the arms or legs or confusion.
  • Efficacy of the procedure is increased to >90% if CRP is performed twice in rapid succession
  • It is not unusual for the patient to lose postural control at the completion of the procedure due to the otoconia briskly falling within the cupula. It is vital that the examiner is in a stance that will provide postural support to the patient.
  • It is important to watch for changes in the nystagmus upon completion of the procedure: a reversal of nystagmus indicates that the otoconia fell back into the canal; an upbeat nystagmus indicates that the otoconia fell back into the cupula.

Procedure:

  • Begin with the patient sitting length-wise on the examination table
  • Place the Frenzel/VNG goggles on the patient
  • Have the patient turn his head to a 45o angle toward the side that you are going to treat (the affected side)
  • While maintaining the 45o head position, guide the patient in a continuous motion from sitting to lying with the head hanging off the table at approximately 20o. IT IS IMPERATIVE TO PROVIDE CERVIAL SUPPORT DURING THIS PORTION OF THE PROCEDURE.
  • Hold this position for 30-60 seconds
  • Maintain the 20o head extension and rotate the patient’s head 90o toward the unaffected side so that the patient’s head is approximately 45o toward the unaffected side
  • Hold this position for 30-60 seconds
  • While still maintaining the 45o head position, guide the patient into a side-lying position on the shoulder of the unaffected side. The patient’s nose should be pointed toward the floor.
  • Hold this position for 30-60 seconds
  • Instruct the patient to tuck his chin and maintain the 45o head position
  • Guide the patient back into a sitting position while ensuring that the patient’s head remains at the 45o angle and the chin remains tucked

**Refer to the attachment in attempting to diagnose affected ear and canal.

References:

  • Epley J. The canalith repositioning procedure: for treatment of benign paroxysmal positional vertigo. Otolaryngol Head Neck Surg 1992;107:399-404
  • Honrubia V, Baloh RW, Harris MR, et al. Paroxysmal positional vertigo syndrome. Am J Otol. 1999;20:465-470
  • Sherman D, Massoud EA. Treatment outcomes of benign paroxysmal positional vertigo. J Otolaryngol 2001;30:295-299.

CRP in the Treatment of BPPV

Posterior Canalithiasis:

  • Evidenced by an upbeat, torsional nystagmus (torsion toward the affected side) that is less than one minute in duration
  • Recommended treatment is the Epley Maneuver of the affected side
  • Alternative treatments might include the Semont Liberatory Maneuver or Brandt-Daroff Exercises

Posterior Cupulothiasis:

  • Evidenced by an upbeat, torsional nystagmus (torsion toward the affected side) that is greater than one minute in duration
  • Recommended treatment is the Semont Liberatory Maneuver
  • Alternative treatments might include Brandt-Daroff Exercises or the Epley CRP

Anterior Canalathiasis:

  • Evidenced by a downbeat, torsional nystagmus (torsion toward the affected side) that is less than one minute in duration
  • Recommended treatment is the Epley CRP performed on the opposite side of the affected ear
  • Alternative treatments might include the Semont Liberatory Maneuver or Brandt-Daroff Exercises

Anterior Cupulothiasis:

  • Evidenced by a downbeat, torsional nystagmus (torsion toward the affected side) that is greater than one minute in duration
  • Recommended treatment is the Semont Liberatory Maneuver
  • Alternative treatments might include Brandt-Daroff Exercises or the Epley CRP
March 2017


With assistance


Without assistance

Helpful Hints:

  • Before recommending any form of positioning maneuver, it is important to ascertain whether the patient has current or past injuries of the neck or spine
  • If possible neurological symptoms occur during the execution of positioning maneuvers, discontinue the procedure IMMEDIATELY and refer for a neurological evaluation. These symptoms might include: blurred vision, numbness, weakness of the arms or legs or confusion.
  • In order for the exercise to be successful, the patient MUST remain in each position until the vertigo subsides PLUS an additional 30 seconds and the patient must perform all 10 revolutions of the exercise. This is time consuming and often traumatic for the patient due to intense vertigo. Therefore, it is vital that the patient is educated on what to expect during the exercise and has agreed to full compliance.
  • Without the patient’s commitment to full compliance, performing the Brandt-Daroff exercises might actually be counter-productive in that otoconia may travel to different parts of the vestibular system and cause a worsening of symptoms.
  • You should instruct the patient that if they are doing the exercise properly, their symptoms will likely lessen in severity with each repetition. However, they should always do the full set of 10 complete revolutions

Procedure:

  • Begin with the patient sitting on his bed
  • The patient will turn his head 45o toward either side
  • The patient moves from sitting position to side-lying position while maintaining the 45o angle of the head (the patient’s nose should be pointed upward)
  • The patient lies in this position until his symptoms have subsided PLUS an additional 30 seconds
  • The patient returns to the sitting position and waits for symptoms to subside PLUS an additional 30 seconds
  • The patient should turn his head in the opposite direction and repeat the exercise

** The above description constitutes one revolution of the exercise. It is recommended that the patient perform ten complete revolutions of the exercise, three times daily.


References:
Brandt T, Daroff RB. Physical therapy for benign paroxysmal positional vertigo. Arch Otolaryngol 1980 Aug;106(8):484-485

Fife TD, et al.(2008). Practice parameter: Therapies for benign paroxysmal positional vertigo (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology, 70(22): 2067–2074.

March 2017

Vestibular Diagnosis and Treatment
A Physical Therapy Approach

Treatment of the left posterior canal:

Turn the head 45° to the right side. Rapidly move into side-lying position on the affected side.  Rapidly move to patients unaffected side with the nose 45° down.

Helpful Hints:

  • Before performing any form of positioning maneuver, it is important to ascertain whether the patient has current or past injuries of the neck or spine.
  • If any possible neurological symptoms occur during the execution of positioning maneuvers, discontinue the procedure IMMEDIATELY and refer for a neurological evaluation. These symptoms might include: blurred vision, numbness, weakness of the arms or legs or confusion.
  • The patient should experience vertigo when moved to each position. If not, it is often useful to perform a slight headshake in an effort to loosen otolithic debris.

Procedure:

  • Begin with the patient sitting on the examination table, facing the examiner, with the patient’s head turned away from the affected side at a 45° angle
  • Guide the patient into a side-lying position toward the affected side. (This should be a rapid movement and the patient’s nose should be pointing upward.)
  • Hold this position for 2-3 minutes
  • While maintaining the 45° head position, guide the patient in a continuous motion from side-lying on the affected side to side-lying on the unaffected side. (The patient’s nose should be pointing downward toward the table.)
  • Hold this position for 3-5 minutes
  • Guide the patient back into a sitting position

References:
Semont, Freyss G, Vitte E. Curing the BPPV with a liberative maneuver. Adv Otorhinolaryngol. 1998;42:290-3

Hughes CA, Proctor L. Benign paroxysmal positional vertigo. Laryngoscope. 1997;107:607-613 

March 2017

Vestibular Diagnosis and Treatment
A Physical Therapy Approach

Treatment of the right posterior canal:

Turn the head 45° to the left side. Rapidly move into side-lying position on the affected side.  Rapidly move to patients unaffected side with the nose 45° down.

Helpful Hints:

  • Before performing any form of positioning maneuver, it is important to ascertain whether the patient has current or past injuries of the neck or spine
  • If any neurological symptoms occur during the execution of positioning maneuvers, discontinue the procedure IMMEDIATELY and refer for a neurological evaluation. These symptoms might include: blurred vision, numbness, weakness of the arms or legs or confusion.
  • The patient should experience vertigo when moved to each position. If not, it is often useful to perform a slight headshake in an effort to loosen otolithic debris.

Procedure:

  • Begin with the patient sitting on the examination table, facing the examiner, with the patient’s head turned away from the affected side at a 45° angle
  • Guide the patient into a side-lying position toward the affected side. (This should be a rapid movement and the patient’s nose should be pointing upward.)
  • Hold this position for 2-3 minutes
  • While maintaining the 45° head position, guide the patient in a continuous motion from side-lying on the affected side to side-lying on the unaffected side. (The patient’s nose should be pointing downward toward the table.)
  • Hold this position for 3-5 minutes
  • Guide the patient back into a sitting position

References
Semont, Freyss G, Vitte E. Curing the BPPV with a liberative maneuver. Adv Otorhinolaryngol. 1998;42:290-3

Hughes CA, Proctor L. Benign paroxysmal positional vertigo. Laryngoscope. 1997;107:607-613

March 2017

Vestibular Diagnosis and Treatment
A Physical Therapy Approach

Treatment of the right anterior canal:

Turn the head 45° to the right side. Rapidly move into side-lying position on the affected side.  Rapidly move to patients unaffected side with the nose 45° upward.

Helpful Hints:

  • Before performing any form of positioning maneuver, it is important to ascertain whether the patient has current or past injuries of the neck or spine.
  • If neurological symptoms occur during the execution of positioning maneuvers, discontinue the procedure IMMEDIATELY and refer for a neurological evaluation. These symptoms might include: blurred vision, numbness, weakness of the arms or legs or confusion.
  • The patient should experience vertigo when moved to the face-down position. If not, it is often useful to perform a slight headshake in an effort to loosen otolithic debris.

Procedure:

  • Begin with the patient sitting toward the side of the examination table with the patient’s head turned toward the affected side at a 45° angle
  • Guide the patient into a side-lying position toward the affected side. (This should be a rapid movement and the patient’s nose should be pointing downward.)
  • Hold this position for 2-3 minutes
  • While maintaining the 45° head position, guide the patient in a continuous motion from side-lying on the affected side to side-lying on the unaffected side. (The patient’s nose should be pointing upward.)
  • Hold this position for 3-5 minutes
  • Guide the patient back into a sitting position

References:
Semont, Freyss G, Vitte E. Curing the BPPV with a liberative maneuver. Adv Otorhinolaryngol. 1998;42:290-3

Hughes CA, Proctor L. Benign paroxysmal positional vertigo. Laryngoscope. 1997;107:607-613

March 2017
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