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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). 

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

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 Setup │ Auto settings.

Setup
Setup │ Auto 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.

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

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

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 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.

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.
  

2.  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
   

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.

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

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.

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.

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. 

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) :

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)

7. 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.
8. Conduct a threshold search using the traditional method for air conduction
9. Repeat for each frequency where a dead region is suspected

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.

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.

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.

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.

 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.

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

• An AC40, AD629 or an AA222 hardware
• A bone conductor

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. 

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

Menu: Click on Menu to access other Audiometry Special tests by going to Menu│Tests. 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. Buttons: Access various tools and features for Tone Audiometry, including High Frequency Audiometry, Multifrequency Audiometry, Automasking, Masking Help and many others. Talk and Monitor: activate/deactivate the Talk Forward and Monitor during testing. Counseling Overlays: Activate/deactivate useful tools when counseling patients about hearing loss. Test symbols: Choose from the available symbols to display on the audiogram, now also including the tinnitus symbol. Comments/Report Editor: Use this feature to add comments relevant to the session. Click on  to collapse/minimize the Tools and Function task bar. 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:

• Instructions for Use for Affinity 2.0/Equinox 2.0.
• Instructions for Use for Callisto™.
• Additional Information for Affinity 2.0/Equinox 2.0.
• Additional Information for Callisto™.

¹ For more information on the Automasking/Masking Help, please refer to the Quick Guide, available on www.interacoustics.com

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.