Download VEMP101: Intro to Vestibular Evoked Myogenic Potentials

Tamaki (2006) VEMP 101
VEMP101: Intro to Vestibular
Evoked Myogenic Potentials
- Getting Started Chizuko Tamaki, Au.D., Ph.D.
Gallaudet University
Washington, DC
Professional Hearing Services
Falls Church, VA
[email protected]
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Agenda
1. “What is VEMP”?
Intro/Background
2. Anatomy & Physiology
3. Procedures
‰ Equipment
‰ Recording
Parameters
‰ Patient Set-Up
‰ Stimulus Parameters
‰
4. Clinical Use
„ Normative range
„ Pathologies
„
„
„
SCD
Endolymphatic
hydrops
Brainstem lesions
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1. INTRO: WHAT IS “VEMP”?
VEMP is…
„
„
„
Vestibular-evoked myogenic potentials
Actually evoked by intense acoustic stimuli,
but through saccule
Response from sternocleidomastoid muscle
(SCM)
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1. Intro
Why use it?
Tests of VOR (e.g.,
Caloric Stimulation,
Rotary Chair, Vestibular
Autorotation)
„
Functions of:
‰
‰
‰
the semicircular canals
primarily superior
vestibular nerve fibers
ascending vestibular
pathway (upper
brainstem)
VEMP
„ Test of vestibulospinal
reflex
„
Functions of:
‰
‰
‰
the saccule
primarily inferior
vestibular nerve fibers
descending vestibular
pathway (lower
brainstem and cervical
spinal cord)
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1. Intro
Background – When should you use it?
„
„
As part of vestibular test battery
When it’s the only vestibular test you can do
‰
‰
„
Young children 1, 2
Deaf patients / patients with severe to profound
HL
Monitoring vestibulospinal reflex functions
over time
‰
‰
Monitoring disease process
Pre- and post- surgery (tumor removal 3 or
cochlear implantation 2)
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1. Sheykholeslami et al. (2005)
2. Jin et al. (2006)
3. Chen, Young & Tseng (2002).
1. Intro
Background – When you may not use it?
„
„
„
„
Conductive hearing loss
Spinal cord injuries
Muscular atrophy
Patients on Valium or other muscle relaxants
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1. Intro
This is VEMP
p13
n23
Inverted Electrodes
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2. ANATOMY & PHYSIOLOGY
ABR
VEMP
VNG/RC/
VAT
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Macula
2. Anatomy & Physiology
VEMP Pathway
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2. Anatomy & Physiology: Pathway
VIIIth Cranial Nerve 1, 2
„
„
Connections between hair cells and the vestibular
nuclei
Travels through the internal auditory canal
cerebellum
SC
HC
S
L
U
IAC
PC
S
M
I
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1. Gacek. (1980).
2. Honrubia & Hoffman. (1997).
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2. Anatomy & Physiology
Sternocleidomastoid Muscle
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2. Anatomy & Physiology
ENG/VNG Caloric Testing Pathway
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3. VEMP PROCEDURES
„
„
„
Equipment
Amplifier Setting
Patient Set-Up
‰
‰
„
Positioning/Posture
Electrode Montage
Stimulus Parameters
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3. Procedures
VEMP Equipment
„
„
Basically most evoked response systems can
be used
Systems that we could record VEMPs
include:
‰
‰
‰
‰
„
ICS CHARTR Evoked Potential System
Bio-logic AEP
Intelligent Hearing Systems SmartEP
Nicolet Spirit
First step – Calibration
‰
Get peak SPL values for your stimuli
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Sample conversion table between peak sound pressure
level (pSPL) and hearing level (dBnHL) by frequency.
(Values based on calibration data for IHS SmartEP)
Intensity
250
500
750
1000
Hz
Max (HL) .
103
107
111
115
HL
Max (pSPL)
130
129
129
130
pSPL
130 pSPL
103
----
----
115
HL
125 pSPL
98
103
107
110
HL
120 pSPL
93
98
102
105
HL
115 pSPL
88
93
97
100
HL
110 pSPL
83
88
92
95
HL
105 pSPL
78
83
87
90
HL
100 pSPL
73
78
82
85
HL
95 pSPL
68
73
77
80
HL
90 pSPL
63
68
72
75
HL
85 pSPL
58
63
67
70
HL
80 pSPL
53
58
62
65
HL
3. Procedure: Equipment
Headphones vs. Insert Earphones
„
Intensity
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3. Procedure: Equipment
SCM Monitoring
„
The level of SCM contraction is linearly correlated
with the amplitude (not so with latency) 1, 2, 3
‰
„
„
If amplitude difference between ears is used as a
diagnostic criterion, then a good quantification of SCM
activity is needed
There are evoked potential instruments with
capabilities to directly monitor the amount of
contraction (EMG)
There are indirect (and less expensive) ways to
ensure stable SCM contraction* if amplitude
symmetry is not an issue 4
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1. Colebatch (1994)
2. Lim et al. (1995)
3. Akin et al. (2004)
4. Vanspauwen et al. (2006)
3. Procedures: Patient Set-Up
Patient positioning
„
„
Goal is contraction of the SCM muscle
No support for or against any particular head
position
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3. Procedures: Patient Set-Up
Electrode Montage
„
Electrodes
‰
„
Over the upper 1/3 of the
SCM belly
Reference electrode
‰
‰
„
Disposable snap-on
electrodes work very well
Active electrodes*
‰
„
Ground
At the sternum with a
jumper, or
At each sternal insertion
High impedance is OK
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*Sheykholeslami et al. (2001).
3. Procedures
Amplifier Setting for Recording
„
„
Filter: 10-30 Hz (high pass) – 1500-3000 Hz (low
pass)
Gain: 2 k (5k at the most)
‰
Be sure that the display scale is set high as well (VEMP
amplitude can be as large as 500 µV)
„
Artifact Reject: off
„
Window: 30 - 40 ms post stimulus
Number of sweeps: 50 to 200
„
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3. Procedures
VEMP Stimulus Parameters
„
Frequency
‰
‰
„
Stimulus Duration
‰
‰
„
Clicks vs. STB (tone pips)
Frequency affects amplitude and threshold
Duration affects latency
If too long or too short, amplitude can be affected
Rate
‰
‰
‰
Most commonly used: 3-6/s
Reduced amplitude with faster rate (>10ms)
Reliable thresholds can be obtained at 13/s
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3. Procedures: Stimuli
Stimulus Frequency & Amplitude
„
1
1.
2.
ASHA Convention
Akin, etc.
2
Akin et al. (2003). The effects of click and tone-burst stimulus parameters on the vestibular evoked
myogenic potential (VEMP). JAAA, 14(9), 500-509.
Rauch
et al. (2004). Vestibular evoked myogenic potentials show altered tuning in patients with Meniere's
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disease. Otol & Neurotol, 25(3), 333-338.
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3. Procedures: Stimuli
Stimulus Frequency & Threshold
1
1.
2.
2
Akin et al. (2003). The effects of click and tone-burst stimulus parameters on the vestibular evoked
myogenic potential (VEMP). JAAA, 14(9), 500-509.
Rauch
et al. (2004). Vestibular evoked myogenic potentials show altered tuning in patients with Meniere's
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disease. Otol & Neurotol, 25(3), 333-338.
3. Procedures: Stimuli
Stim. Frequency & Latencies
1
1.Tamaki
Rauch
2006et al. (2004).
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2. Akin et al. (2003).
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3. Procedures: Stimuli
Stimulus Duration
„
STB
‰
‰
‰
2 cycle rise/fall time with
no plateau is common
1 ms rise/fall time with 5
ms plateau time gives
most prominent
amplitude for 500 Hz
(Cheng & Murofushi,
2001).
7 ms duration for 500 / 1k
Hz produces greatest
amplitude (Welgampola
& Colebatch, 2001)
„
Clicks
‰
‰
0.1 ms most widely
reported
0.5 ms was shown to
produce the optimal
response (Huang et al.,
2005)
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3. Procedures: Stimuli
Stimulus Rate
„
Most published articles (75/80, up to 2005)
used 3-6/s
‰
„
5/s the most popular choice
If you were to determine thresholds (and at
multiple frequencies), this would take a lot of
time
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Proportion of subjects whose thresholds within +/- 1 step size re:
5.1/s thresholds in both ears vs. those whose thresholds beyond
+/- 1 step size re: 5.1/s in at least one ear. 1 step size = 5 dB.
Number of Subjects (N=20)
20
Subjects:
10 men
10 women
15
Age 20-30 yrs
Normal hearing
up to 2kHz
10
5
No hx of
dizziness/
balance
problems
≥ 2 step sizes
≤ -2 step sizes
within +/- 1 step size
250 Hz
500 Hz
750 Hz
1000 Hz
17.1/s
15.1/s
13.1/s
11.1/s
17.1/s
15.1/s
13.1/s
11.1/s
17.1/s
15.1/s
13.1/s
11.1/s
17.1/s
15.1/s
13.1/s
11.1/s
0
No hx of
neurological
conditions
No medications/
alcohol
consumption
prior to testing
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3. Procedures: Stimulus Summary
Recommended Stimulus Characteristics
„
„
„
Frequencies 250, 500, 1k, click or 2k
Duration
2 cycle rise/fall; 0.1 or 0.5ms
Rep Rate
13/s for thresholds
5/s for amplitude and latencies
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3. Procedures
Common Mistakes
„
„
„
„
„
Stimulating the opposite ear to the activated
SCM
Electrode is placed away from the SCM
Not enough SCM contraction
Gain is set too high
Display scale is set too low
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4. CLINICAL USE
„
„
Normative Range
Looking at some pathologies
‰
‰
‰
SCD
Meniere’s Disease
Brainstem lesions
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4. Clinical Use: Norms
Amplitude – Clicks
500
Amplitude Mean (uV)
400
300
Amplitude means reported, from the
smallest to the largest. Open points
indicate multiple data points from the same
study. Bars represent 1 standard
deviation.
200
100
0
1
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3
5
7
9
11
13
15
Data Set
Articles included in the meta-analysis
Cheng, P.W., Huang, T.W. & Young, Y.H. (2003). The influence of clicks versus short tone bursts on the
vestibular evoked myogenic potentials. Ear & Hearing, 24(3), 195-197.
Colebatch, J.G., Halmagyi, G.M. & Skuse, N.F. (1994). Myogenic potentials generated by a click-evoked
vestibulocollic reflex. Journal of Neurology, Neurosurgery, & Psychiatry, 57(2), 190-197.
Ferber-Viart, C., Duclaux, R., Colleaux, B. & Dubreuil, C. (1997). Myogenic vestibular-evoked potentials in
normal subjects: a comparison between responses obtained from sternomastoid and trapezius
muscles. Acta Oto-Laryngologica, 117(4), 472-781.
Huang, T.W., Su, H.C. & Cheng, P.W. (2005). Effect of click duration on vestibular-evoked myogenic
potentials. Acta Oto-Laryngologica, 125(2), 141-144.
Itoh, A., Kim, Y.S., Yoshioka, K., Kanaya, M., Enomoto, H., Hiraiwa, F., et al. (2001). Clinical study of
vestibular-evoked myogenic potentials and auditory brainstem responses in patients with brainstem
lesions. Acta Oto-Laryngologica Suppliment, 545, 116-119.
Lim, C.L., Clouston, P., Sheean, G. & Yiannikas, C. (1995). The influence of voluntary EMG activity and
click intensity on the vestibular evoked myogenic potential. Muscle Nerve. 18 (10), 1210-1213.
Murofushi, T., Shimizu, K., Takegoshi, H. & Cheng, P.W. (2001). Diagnostic value of prolonged latencies in
the vestibular evoked myogenic potential. Archives of Otolaryngology – Head & Neck Surgery, 127(9),
1069-1072.
Ochi, K., Ohashi, T. & Nishino, H. (2001). Variance of vestibular-evoked myogenic potentials.
Laryngoscope, 111(3), 522-527.
Patko, T., Vidal, P.P., Vibert, N., Tran Ba Huy, P., & de Waele, C. (2003). Vestibular evoked myogenic
potentials in patients suffering from an unilateral acoustic neuroma: a study of 170 patients. Clinical
Nuerophysiology, 114(7), 1344-1350.
Robertson, D.D. & Ireland, D.J. (1995). Vestibular evoked myogenic potentials. Journal of Otolaryngology,
24, 3-8.
Sartucci, F. & Logi, F. (2002). Vestibular-evoked myogenic potentials: a method to assess vestibulo-spinal
conduction in multiple sclerosis patients. Brain Research Bulletin, 59, 59-63.
Su, H.C., Huang, T.W., Young, Y.H. & Cheng, P.W. (2004). Aging effect on vestibular evoked myogenic
potential. Otology & Neurotology, 25(6), 977-980.
Takegoshi, H. & Murofushi, T. (2000). Vestibular evoked myogenic potentials in patients with
spinocerebellar degeneration. Acta Oto-Laryngologica, 120(7), 821-824.
Takeichi, N., Sakamoto, T., Fukuda, S. & Inuyama, Y. (2001). Vestibular evoked myogenic potential
(VEMP) in patients with acoustic neuromas. Auris Nasus Larynx, 28, S39-41.
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4. Clinical Use: Norms
400
100
350
90
80
300
70
250
60
200
50
150
40
30
100
20
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0.0
5.1/s
13.1/s
5.1/s
13.1/s
250 Hz
13.1/s
0
5.1/s
0
13.1/s
10
5.1/s
50
500 Hz 750 Hz 1000 Hz
„
Akin et al. (2003)
Rauch et al. (2004)
„
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„
Corrected Amplitude
Amplitude (m icroV)
Amplitude - STB
‰
‰
‰
‰
N=20
Normal adults (20-30yo)
Stim: 4-cycle (total)
Blackman envelope
Corrected Amplitude =
raw amplitude / RMS of
pre-stimulus EMG*
* Welgampola & Colebatch (2001). Vestibulocollic reflexes:
normal values and the effect of age. Clinical Nuerophysiology,
112, 1971-1979.
4. Clinical Use: Norms
Amplitude Ratio:│R-L│/(R+L)
„
Young et al. (2002) suggested cut-off ratio of
.36.
„
You need a really good EMG level monitoring
system to yield an accurate symmetry ratio
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4. Clinical Use: Norms
Threshold - Clicks
1. Akin, et al. (2003). N = 19.
Mean ± 1 SD in dBSPL.
Age range: 22-51 yrs
150
Threshold (dB SPL)
140
2. Colebatch, et al. (1994). N = 10.
Max – Min in dBSPL.
Age range: 29-63 yrs
130
120
3. Ochi & Ohashi (2003). N = 60.
Overall mean ± 1 SD in dBSPL.
Age range: 20-77 yrs
110
100
90
80
dBHL
70
0
1
2
3
4
4. Welgampola & Colebatch (2001).
Overall mean ± 1 SD in dBSPL.
Age range: 25-85 yrs N = 70.
♦: mean of subj. 25-29 yrs N = 12?
◊: mean of subj. 70-85 yrs N = 11?
5. Ochi, et al. (2001). N = 18.
Mean ± 1 SD in dBnHL.
Age range: 21-38 yrs
5
Study
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4. Clinical Use: Norms
Threshold - STB
125
„
„
Akin et al. (2003)
Rauch et al. (2004)
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‰
‰
‰
N=20
Normal adults (20-30yo)
Standard deviation =
approx. 6 dB
120
Intensity (dB pSPL)
„
115
110
105
100
95
90
250
500
750
1000
Frequency (Hz)
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4. Clinical Use: Norms
Latencies - Clicks
30
p13
n23
Latency (ms)
25
20
18
15
2
5
9
4
8
7
12
10
3
13
6
11
14
16
15
17
1
10
5
2
5
4
1
9
8
7
1
2
1
0
3
1
3
6
1
1
1
4
1
5
1
8
1
6
1
7
Data Set
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4. Clinical Use: Norms
Latencies - STB
„
See Akin et al. and
Rauch et al.
„
Variability in latency
within individuals has
been observed
Example: Two successive runs of
a 28 yo male subject at 250 Hz.
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4. Clinical Use
Pathologies that may cause abnormal VEMPs
„
Labyrinthine pathologies
‰ Superior canal
dehiscence (SCD)
syndrome
‰ Endolymphatic Hydrops
‰ Labyrinthitis involving
saccule
‰ Labyrinthine ossification
(Meningitis)
‰ Connexin 26?
„
VIIIth CN pathologies
‰ Vestibular neuritis
‰ Acoustic neuroma
„
Brainstem Lesions
‰ Multiple Sclerosis
‰ Stroke
‰ Tumor
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4. Clinical Use: Pathologies
Superior Canal Dehiscence (SCD)
Gray, H. (1918). FIG. 138 .
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Cox, Lee, Carey, & Minor (2003). Binaural SCD
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4. Clinical Use: Pathologies
SCD
Normal Inner Ear
SCD
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Threshold in
dBnHL
(+45 dB for SPL)
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Colebatch et al. (1998). Vestibular hypersensitivity to
clicks is characteristic of the Tullio phenomenon.
Journal of Neurology, Neurosurgery, & Psychiatry.
65(5), 670-678.
4. Clinical Use: Pathologies
SCD Summary
„
The major symptom is …
dizziness with loud
sound and pressure
Also possible in the head hanging position
„
„
„
Audiogram may show a ….
conductive
component
VEMP results show …
low thresholds and large
amplitudes
Definitive diagnosis has to be made by …
CT
scans
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4. Clinical Use: Pathologies
Endolymphatic Hydrops
Normal Inner Ear
Hydropic Inner Ear
Northwestern University,
cited in: Hain, TC (n.d.).
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4. Clinical Use: Pathologies
Endolymphatic Hydrops
„
„
Absent or decreased VEMP in 22/42 pts (51%) w/
Meniere’s disease 1
Positive Glycerol VEMP 2
‰
‰
„
Unilateral Meniere’s disease (8/15; 53%)
67% detected w/ combined transtympanic EcochG
glycerol dehydration and GVEMP
Cochlear vs. saccular hydrops
‰
‰
DPOAEs and VEMP in the work-up for early hydrops 3
VEMP can be used rather than EcochG when patient
has too severe of a hearing loss
1. Murofushi T, et al. (2001).
2. Shojaku H, et al. (2001).
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3. Magliulo et al. (2004)
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4. Clinical Use: Pathologies
Endolymphatic Hydrops
„
Altered frequency tuning
in Meniere’s disease
patients even in the
unaffected ears1
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1. Rauch SD, et al. (2004).
4. Clinical Use: Pathologies
Other pathologies along the reflex arc
When you see:
„ Diminished or absent
response
„ Asymmetry
„ Poor morphology
Any pathology along the VEMP pathway
can lead to poor VEMP recording
Check:
„ Ipsilateral SCM is
contracted
„ Scaling on the screen is
appropriate
„ Stimulus characteristics
„ Electric noises in the
room
„ Electrode placement
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Itoh et al. (2001).
In Summary…
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Sample Result Chart
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Questions?
„
Thank you!
„
Email: [email protected]
„
Ppt copies will be on ASHA website
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References:
*Akin et al. (2003). The effects of click and tone-burst
stimulus parameters on the vestibular evoked myogenic
potential (VEMP). JAAA, 14(9), 500-509.
Akin et al. (2004). The influence of voluntary tonic EMG level
on the vestibular-evoked myogenic potential. J Rehabil
Res Dev, 41(3B), 473-80.
Bickford, Jacobson & Cody. (1964). Nature of averaged
evoked potentials to sound and other stimuli in man. Ann
N.Y. Acad Sci. 112, 204-223.
Chen, Young, & Tseng. (2002). Preoperative versus
postoperative role of vestibular-evoked myogenic
potentials in cerebellopontine angle tumor. Laryngoscope,
112(2), 267-71.
*Cheng, Huang, & Young. (2003). The influence of clicks
versus short tone bursts on the vestibular evoked
myogenic potentials. Ear & Hearing, 24(3), 195-197.
Cheng & Murofushi (2001). The effects of plateau time on
vestibular-evoked myogenic potentials triggered by tone
bursts. Acta Otolaryngol, 121(8), 935-8.
Colebatch & Halmagyi. (1992). Vestibular evoked potentials
in human neck muscles before and after unilateral
vestibular deafferentation. Neurology, 42, 1635-6.
*Colebatch, Halmagyi, & Skuse. (1994). Myogenic potentials
generated by a click-evoked vestibulocollic reflex. Journal
of Neurology, Neurosurgery, & Psychiatry, 57(2), 190-197.
Colebatch et al. (1998). Vestibular hypersensitivity to clicks is
characteristic of the Tullio phenomenon. J Neurol
Neurosurg & Psychiatry. 65(5), 670-678.
Cox, Lee, Carey, & Minor (2003). Dehiscence of bone
overlying the superior semicircular canal as a cause of an
air-bone gap on audiometry: a case study. Am J Audiol,
12, 11-6.
da Costa, de Sousa, & Piza (2002). Meniere’s disease:
overview, epidemiology, and natural history. Otolaryngol
Clin North Am, 35(3), 455-95.
*Ferber-Viart et al. (1997). Myogenic vestibular-evoked
potentials in normal subjects: a comparison between
responses obtained from sternomastoid and trapezius
muscles. Acta Oto-Laryngol, 117(4), 472-781.
Gacek. (1980). Clinical inferences from recent observations
on vestibular neuro-anatomy. Journal of Otolaryngology,
9(1), 44-52.
Honrubia & Hoffman. (1997). Practical anatomy and
physiology of the vestibular system. In: Jacobson,
Newman, & Kartush. (Eds). Handbook of Balance Function
Testing. San Diego, CA: Singular.
*Huang, Su, & Cheng. (2005). Effect of click duration on
vestibular-evoked myogenic potentials. Acta OtoLaryngologica, 125(2), 141-144.
*Itoh, et al. (2001). Clinical study of vestibular-evoked
myogenic potentials and auditory brainstem responses in
patients with brainstem lesions. Acta Oto-Laryngol (Suppl),
545, 116-119.
Jin, et al. (2006). Vestibular-evoked myogenic potentials in
cochlear implant children. Acta Otolaryngol, 126(2):164-9.
*Lim, et al. (1995). The influence of voluntary EMG activity
and click intensity on the vestibular evoked myogenic
potential. Muscle Nerve. 18 (10), 1210-3.
Magliulo et al. (2004). Vestibular evoked myogenic potentials
and distortion-product otoacoustic emissions combined
with glycerol testing in endolymphatic hydrops: their value
in early diagnosis. Ann Otol Rhinol Laryngol, 113(12),
1000-5.
*Murofushi, et al. (2001). Diagnostic value of prolonged
latencies in the vestibular evoked myogenic potential.
Archives of Otolaryngology – Head & Neck Surgery, 127(9),
1069-1072.
*Ochi & Ohashi (2003). Age-related changes in the
vestibular-evoked myogenic potentials. Otolaryngol Head
Neck Surg, 129(6), 655-9.
*Ochi, Ohashi, & Nishino. (2001). Variance of vestibularevoked myogenic potentials. Laryngoscope, 111(3), 522527.
*Patko, et al. (2003). Vestibular evoked myogenic potentials
in patients suffering from an unilateral acoustic neuroma: a
study of 170 patients. Clin Nuerophysiol, 114(7), 13441350.
Rauch et al. (2004). Vestibular evoked myogenic potentials
show altered tuning in patients with Meniere's disease.
Otol & Neurotol, 25(3), 333-338.
*Robertson & Ireland. (1995). Vestibular evoked myogenic
potentials. J Otolaryngol, 24, 3-8.
*Sartucci & Logi. (2002). Vestibular-evoked myogenic
potentials: a method to assess vestibulo-spinal conduction
in multiple sclerosis patients. Brain Res Bulletin, 59, 59-63.
*Sheykholeslami et al. (2001). The effect of
sternocleidomastoid electrode location on vestibular
evoked myogenic potential. Auris Nasus Larynx, 28(1),
41-43.
Sheykholeslami et al. (2005). Vestibular-evoked myogenic
potentials in infancy and early childhood. Laryngoscope,
115(8), 1440-4.
Uchino et al. (1994). Monosynaptic and disynaptic
connections in the utriculo-ocular reflex arc of the cat. J
Neurophysiol., 71(3), 950-8.
Shojaku, et al. (2001). Clinical usefulness of glycerol
vestibular-evoked myogenic potentials: preliminary report.
Acta Otolaryngol Suppl, 545, 65-8.
*Su, et al. (2004). Aging effect on vestibular evoked
myogenic potential. Otology & Neurotology, 25(6), 977980.
*Takegoshi, & Murofushi. (2000). Vestibular evoked
myogenic potentials in patients with spinocerebellar
degeneration. Acta Oto-Laryngol, 120(7), 821-4.
*Takeichi, et al. (2001). Vestibular evoked myogenic
potential (VEMP) in patients with acoustic neuromas.
Auris Nasus Larynx, 28, S39-41.
*Vanspauwen et al. (2006). Improving vestibular evoked
myogenic potential reliability by using a blood pressure
manometer. Laryngoscope, 116(1), 131-5.
*Welgampola & Colebatch (2001). Vestibulocollic reflexes:
normal values and the effect of age. Clin Nuerophysiol,
112, 1971-1979.
Young, Wu & Wu (2002). Augmentation of vestibular evoked
myogenic potentials: an indication for distended saccular
hydrops. Laryngoscope, 112(3), 509-12.
Zapala & Brey (2004). Clinical experience with the vestibular
evoked myogenic potential. JAAA, 15(3), 198-21.