Vestibular Diagnosis and Treatment
A Physical Therapy Approach
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Head roll to the right | Head roll to the left |
Helpful Hints
Procedure:
Results:
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
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:
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.
Vestibular Diagnosis and Treatment
A Physical Therapy Approach
Treatment of the left horizontal canal:
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Roll the patient's body toward the unaffected side. | Roll the patient into the prone position. |
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Roll the patient's body toward the affected side. |
Helpful Hints:
Procedure:
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
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
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
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.
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
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 |
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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 |
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Presentation |
Oddball paradigm |
Oddball paradigm |
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Intensity |
60-80dB peSPL |
60-80dB peSPL |
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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 |
Pre stimuli -100ms Post stimuli 700ms or more |
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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 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.
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.
Vestibular Diagnosis and Treatment
A Physical Therapy Approach
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Start with patient sitting up. |
Rapidly move to a Side-lying position. |
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Quickly position head at a 45 degree angle with nose |
Helpful Hints:
Procedure:
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.
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
Vestibular Diagnosis and Treatment
A Physical Therapy Approach
Treatment of the left anterior canal:
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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:
Procedure:
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
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.
Vestibular Diagnosis and Treatment
A Physical Therapy Approach
Dix-Hallpike test performed to the right:
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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:
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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:
Procedure
References:
Posterior Canalithiasis
Posterior Cupulothiasis
Anterior Canalathiasis
Anterior Cupulothiasis
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.
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.
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
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.
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 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.
Vestibular Diagnosis and Treatment
A Physical Therapy Approach
Epley Maneuver for right posterior canal BPPV:
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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°. |
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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. |
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While keeping the head in 45°, tucked position, |
Helpful Hints:
Procedure:
**Refer to the attachment in attempting to diagnose affected ear and canal.
References:
Posterior Canalithiasis:
Posterior Cupulothiasis:
Anterior Canalathiasis:
Anterior Cupulothiasis:
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.
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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.
Vestibular Diagnosis and Treatment
A Physical Therapy Approach
Treatment of the left posterior canal:
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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:
Procedure:
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
Vestibular Diagnosis and Treatment
A Physical Therapy Approach
Treatment of the right anterior canal:
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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:
Procedure:
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
With assistance
Without assistance
Helpful Hints:
Procedure:
** 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.
Vestibular Diagnosis and Treatment
A Physical Therapy Approach
Treatment of the right posterior canal:
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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:
Procedure:
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