bera or abr
DESCRIPTION
BRAIN STEM RESPONSE AUDIOMETRYTRANSCRIPT
BERA (ABR) and Its Variants
KUNNAMPALLIL GEJO JOHN,
BASLP,MASLP
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BERA (ABR) Agenda
• Agenda:
► Click Air Conduction ABR
► Toneburst Air Conduction ABR
► Click Bone Conduction ABR
► Stacked Auditory Brainstem Response
► CHAMP – Cochlear Hydrops Analysis Masking Procedure
► BioMAP – Biological Marker of Auditory Processing
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Click Air Conduction ABR
• Click air conduction ABR is a good starting point
► Gives you good general information about waveform
morphology and general idea of patient’s hearing level
• If you use click air conduction ABR in isolation:
► Cannot infer hearing loss configuration
► Do not have adequate information for a hearing aid fitting.
• The click air conduction ABR can miss both low and
high frequency hearing loss.
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Example of Electrode Montage
• Electrode Montage
► 1) Non-Inverting Cz or high forehead - sometimes if an
infant has a large soft spot it is difficult to get low
impedance.
► 2) Inverting A1 and A2 - use the earlobe instead of the
mastoid, so that if bone conduction is needed you will
have less placement difficulties with oscillator.
► 3) Inverting C7 (nape) – for infants using C7 instead of
A1 and A2 can help increase amplitude of wave V,
however you will decrease detection of wave I.
► 4) Ground - usually center of forehead
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Example of Click Parameters
• EQUIPMENT PARAMETERS
► Two Channel Recording
• Cz to A1 or C7
• Cz to A2 or C7
► Hi Filter (Low Pass)- 1500 Hz (3000)
► Lo Filter (High Pass) - 30 Hz (100)
► 20 MS Window
► Rate 13.3
► Gain – 100,000 (150,000)
► Points (Sampling Rate) – 256 (512)
► Rarefaction Click (Alternating to rule out cochlear
microphonic)
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Click Air Conduction ABR
• Threshold Search ABR
► Start at a moderate level - 60 dB nHL
► If wave V is present, decrease to 30 dB nHL
► If present, decrease to 20 dB nHL. This is within normal limits.
► If not present at 30 dB, bracket at 40 or 50 dB depending on
latency of response.
► If no response at 60 dB, increase to 80 dB.
► 20 dB or below is within normal limits
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Click Air Conduction ABR
• High Intensity Infant ABR
► Perform ABR at 75 dB nHL to evaluate waveform morphology
• Wave Morphology - Infants may have a larger Wave I than Wave V
• Evaluate Wave I to V Interpeak Latency
• Change polarities to look for cochlear microphonic (used as a
diagnostic tool in auditory neuropathy/dys-synchrony)
• High Intensity Adult ABR
► Perform ABR at high intensity to evaluate for retrocochlear
pathology
• Latency (interaural and absolute)
• Change stimulus rate to evaluate neural synchrony
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Click Air Conduction ABR
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Toneburst Air Conduction ABR
• Provides frequency specific information
• Can diagnose low and high frequency hearing loss.
• May take several attempts to replicate a wave
• Toneburst Stimuli
► Blackman ramping - (commonly used)
• Toneburst ABR is needed to determine if the infant has a
high frequency hearing loss (such as infants given ototoxic
medications).
• Helps determine the configuration of the hearing loss which
assists in selecting proper amplification device.
• Electrode Montage
► Can use the same as click air conduction ABR
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Toneburst Air Conduction ABR
• 500 Hz
► Response is a broad rounded peak about 4 to 8 ms longer
than the click
► Cyclical stimulus ringing sometimes occurs - this is not a
response.
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Click Bone Conduction ABR
• The click bone conduction ABR provides a
differential diagnosis of the type of hearing loss
(sensorineural vs. conductive vs. mixed)
• Provides the information you need to better
counsel and make your next step toward
intervention/habilitation.
• One way to diagnose hearing loss in patients
with craniofacial anomalies (aural atresia)
• Indicator of middle ear dysfunction in infants.
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Click Bone Conduction ABR
• Electrode Montage and Transducer Placement
► Same as click air conduction ABR
► Always use earlobe instead of mastoid placement.
► Bone oscillator headbands are often too big for infants.
Hand-held placement can be used. Firmly hold the
oscillator to the infant’s mastoid with 1 index finger. Push
the oscillator on the mastoid until you could almost push
the child’s head away from you.
► Transducer placement should be consistent to reduce
variability. Never use 2 fingers to hold it as this can
dampen the output.
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Click Bone Conduction ABR
• EQUIPMENT PARAMETERS
► One Channel Recording – using electrode switching in Bio-
logic system.
• Channel 1, input 1: (CZ)
• Channel 1, input 2: (Left earlobe)
• Common/ground: (Right earlobe)
► Two Channel Recording
• Cz to A1
• Cz to A2
► Alternating Click - minimizes artifact
• More information
► Perform Biologic Calibration to determine what correction
factors are needed.
► Always replicate your waveforms
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Click Bone Conduction ABR
• Threshold Search ABR
► Start at a moderate level - 30 dB nHL. If you start too
high the infant may wake up
► Do not exceed 50 dB nHL. You will overdrive the
oscillator.
► Decrease in 10 dB steps
► Perform your own clinic norms, typically 20 dB nHL and
below is within normal limits
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Sample of Bone Conduction
ABR Response
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A Brief Introduction to Stacked ABR
and Cochlear Hydrops Analysis
Masking Procedure (CHAMP)
Prepared for Bio-logic Systems Corp. by
Manuel Don, Ph.D. / Betty Kwong, M.S.
Electrophysiology Department
House Ear Institute, Los Angeles, CA
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Normal Internal Auditory Canal (IAC)
Standard
ABR High-frequency
Facial Nerve
Acoustic Nerve
Sup.
Vest. Nerve
Inf.
Vest. Nerve
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Abnormal
Standard
ABR
Medium or Large Tumor in IAC
Facial Nerve
Acoustic Nerve
Sup.
Vest. Nerve
Inf.
Vest. Nerve
Tumor
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Abnormal
Standard
ABR
Small Tumor in IAC
Facial Nerve
Acoustic Nerve
Sup.
Vest. Nerve
Inf.
Vest. Nerve
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Small Tumor in IAC
Facial Nerve
Acoustic Nerve
Normal
Standard
ABR
Sup.
Vest. Nerve
Inf.
Vest. Nerve
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Normal IAC
Facial Nerve
Acoustic Nerve
Sup.
Vest. Nerve
Inf.
Vest. Nerve
Stacked ABR
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Normal IAC
Facial Nerve
1 2
3
4 5
Acoustic Nerve
Sup.
Vest. Nerve
Inf.
Vest. Nerve
Stacked
ABR
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Diagnostic Test: If you add the activity from each
of the five areas, is the amplitude normal?
Activity from area 1 +
Activity from area 2 +
Activity from area 3 +
Activity from area 4 +
Activity from area 5
1
2
3
4
5
Normal Amplitude
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3
Medium or Large Tumor in IAC
Abnormal
Stacked ABR
Normal Tumor
Acoustic Nerve
1
2
3
4
5
Tumor
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Small Tumor in IAC
Normal Tumor
Acoustic Nerve
1
2
3
4
5
Abnormal
Stacked ABR
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Small Tumor in IAC Missed by Standard ABR
Facial Nerve
Acoustic Nerve
Normal
Standard
ABR
Sup.
Vest. Nerve
Inf.
Vest. Nerve
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Small Tumor in IAC
Normal Tumor
Acoustic Nerve
1
2
3
4
5
Abnormal
Stacked ABR
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Stacked ABR Measure
Requirements Proposed Methods
1. An auditory signal that stimulates => Wide-band Click
essentially all frequency regions of the
cochlea
2. A method for separating the => The Derived-band
responses from different frequency ABR Technique
regions of the cochlea
3. A procedure for summing => The Stacking
responses to approximate total neural Technique
activity
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TDH-49
8.0
Click
High-pass Masking Noise
(8.0, 4.0, 2.0, 1.0, and 0.5 kHz)
4.0 2.
0
1.0 2.
0
0.5
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M M
M M M
M M M M
M M M M M
ApexFrequency kHz
8 4 2 1 0.5Base
M
Unmasked
8.0 kHz
4.0 kHz
2.0 kHz
1.0 kHz
0.5 kHz
Click Alone
Click Alone and
High Pass Noise Responses
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CONCLUSION
The Stacked ABR appears to have better sensitivity
and specificity than the standard ABR for small ( < 1
cm) tumors.
In other words, the Stacked ABR is better at :
1. detecting small tumors, and
2. decreasing the number of misdiagnosed
non-tumor patients (i.e., decreasing the
number of false-positives referred for
MRI).
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Endolymphatic Hydrops
Changes how cochlea processes
auditory stimuli
Alters Basilar Membrane Parameters
(e.g., stiffness, fluid column height, etc.)
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In Meniere’s disease, we think that:
Cochlear hydrops alters the response properties of the basilar
membrane.
Low frequency masking noise is less effective for masking activity
in higher frequency regions.
Thus, we observe undermasking in the high pass responses.
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14121086420 ms
Unmasked
8.0 kHz
4.0 kHz
2.0 kHz
1.0 kHz
0.5 kHz
ABR to Click Alone (unmasked)
ABR to Click + 8 kHz HPN
ABR to Click + 4 kHz HPN
ABR to Click + 2 kHz HPN
ABR to Click + 1 kHz HPN
ABR to Click + 0.5 kHz HPN
Click Alone (Unmasked)
and High Pass Noise (HPN) Responses
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14121086420 ms
Unmasked
8.0 kHz
4.0 kHz
2.0 kHz
1.0 kHz
0.5 kHz
non-Meniere’s disease
Undermasking in Meniere’s Disease
Unmasked
8.0 kHz
4.0 kHz
2.0 kHz
1.0 kHz
14121086420
0.5 kHz
Meniere’s disease
ms
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Wave V Latency Delay
(500 Hz HP – Click Alone)
non-Meniere’s disease
14121086420 ms
Unmasked
8.0 kHz
4.0 kHz
2.0 kHz
1.0 kHz
0.5 kHz
ms
Unmasked
8.0 kHz
4.0 kHz
2.0 kHz
1.0 kHz
14121086420
0.5 kHz
Meniere’s disease
ms
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-1 0 1 2 3 4 5 6 7
0
10
20
30
40
50
60
70
80
90
100 0
10
20
30
40
50
60
70
80
90
100
Wave V Latency Delay (500 Hz HP - Click Alone) in ms
% S
en
sit
ivit
y
Normal - typical wave V (N = 35)
Normal - undermasked wave V (N = 3)
Meniere’s (N = 20)
Wave V Latency Delay
(500 Hz HP – Click Alone)
100
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IMPORTANT!
Do not confuse the Stacked ABR method with
this method for evaluating Meniere’s disease.
The Stacked ABR is for small tumor detection
and is not used for Meniere’s disease assessment.
Stacked ABR uses the sum of the aligned
derived-band (subtracted) ABRs while the Meniere’s
test uses only the high-passed noise masked
responses to clicks.
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Staff Acknowledgements
Department of Electrophysiology
Manuel Don, Ph.D.
Betty Kwong, M.S., CCC-A
Erin Maloff, M.S., CCC-A
Michael Waring, Ph.D.
Department of Clinical Studies
Ann Masuda, M.S., CCC-A
Chiemi Tanaka, M.A., CCC-A
Department of Histopathology
Fred Linthicum, M.D.
Physicians at the House Ear Clinic
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Support
NIH/NIDCD 1R43 DC04141
Raviv (PI)
NIH/NIDCD 2R44 DC04141 Raviv
(PI)
NIH/NIDCD R01 DC03592 Don
(PI)
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Don M, Masuda A, Nelson RA, and Brackmann DE (1997). Successful
Detection of Small Acoustic Tumors Using the Stacked Derived Band
ABR method. Am J Otolaryngol.; 18: 608-621.
Don M and Kwong B (2002). Auditory Brainstem Response:
Differential Diagnosis. In: Katz J, Eds. Handbook of Clinical
Audiology, Fifth Edition. Pennsylvania: Lippincott Williams &
Wilkins Publishing; pp. 274-297.
Don M (2002). Auditory brainstem response testing in
acoustic neuroma diagnosis. Current Opinion in
Otolaryngology & Head and Neck Surgery 10:376-381.
Don M, Kwong B, Tanaka C, Brackmann DE, Nelson RA (2005) The
Stacked ABR: A Sensitive and Specific Screening Tool for Detecting
Small Acoustic Tumors (Audiology & Neurotology 10: 274-290)
Don M, Kwong B, Tanaka C (2005) A Diagnostic Test for Meniere’s
Disease and cochlear Hydrops: Impaired High-pass Noise Masking
ABRs. (Otology & Neurotology 26: 711-722.)
References
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All Slides on Stacked & CHAMP
are from House Ear Institute
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• The Auditory Neuroscience Laboratory at Northwestern University was founded in 1990 by Nina Kraus, Ph.D.
Who developed BioMAP?
• Together with her colleagues, staff and graduate students, Dr. Kraus has been investigating neural encoding of complex sounds such as speech and music in normal listeners and a variety of clinical
populations.
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What is BioMAP?
“Biological Marker of Auditory Processing”
An electrophysiologic response,
measured at the level of the
brainstem, that mimics
characteristics of the speech
stimulus /da/ used to evoke it.
BioMAP data collection is very
similar to a standard click ABR.
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For what population is BioMAP used?
Studies on children from 8-12 years old have shown that the BioMAP response is abnormal in approximately 30% of children who have been diagnosed with various learning problems such as: •Dyslexia •Central Auditory Processing Disorder (CAPD) •Specific Language Impairment •Learning Disability (LD) •Attention Deficit Hyperactivity Disorder (ADHD)
LD
SLI
ADHD
Dyslexia
CAPD
Auditory
perception &
Neural encoding
deficits
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For what population is BioMAP used?
The 30% of the children with known Learning Problems who also have abnormal BioMAP responses tend to be:
Behavioral Manifestations poorest readers - WRAT (Wide Range Achievement Test) poorest spellers - WRAT poorest auditory processing - Woodcock Johnson
poor fine-grained speech syllable discrimination excessive backward masking slower speed of processing - Woodcock Johnson
Cortical Consequences (revealed in challenging listening situations) abnormal cortical response in noise (P1/N1/P2) fine-grained stimulus differences not encoded (MMN)
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The Brainstem response reflects the
acoustic characteristics of speech
with remarkable fidelity.
What is the physiological event upon which BioMAP was developed?
BioMAP Theory
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Speech Source vs. Filter Characteristics
Filter Source
vocal folds vocal
folds
source + filter = speech sound
Fundamental frequency (F0) + harmonics Formants (F1, F2, F3) resonance of vocal tract
frequencies depend on position of lips, tongue
Frequency:
Together the source and filter combine to create a spectrally and temporally complex
waveform.
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Stimulus/Response Comparison
0 10 20 30 40 50 60
stimulus (filtered to mimic low-pass characteristic of the midbrain)
response a very nice match!
0 250 500 750 1000 1250 1500
time domain frequency domain
Time (ms) Frequency (Hz)
Courtesy of Auditory Neuroscience Laboratory, Northwestern University. Nina Kraus, Director.
BioMAP Theory Brainstem response to speech can be viewed in the same ways.
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Neural Event
modified from Kraus and Nicol, TRENDS in Neurosciences, 2005
~ 120 Hz ~ 120 Hz
“da”
A
V lll
l
C O
E F D
~ 120 Hz ~ 120 Hz
0 10 20 30 40 50 60
Time (ms)
Courtesy of Auditory Neuroscience Laboratory, Northwestern University. Nina Kraus, Director.
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What happens to the BioMAP response after auditory training?
The BioMAP response IMPROVES with auditory
training as do other behavioral measures.
So, the post-training BioMAP response can be
used as an objective test to verify the benefit
of auditory training.
EVIDENCE BASED PRACTICE!!
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What characteristics of the BioMAP response are used in the analysis?
The abnormal BioMAP children have reduced amplitudes
High Frequencies F1
Hz
LP
NL
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What characteristics of the BioMAP response are used in the analysis?
6 7 8 9 10-0.8
-0.6
-0.4
-0.2
0
0.2
time (ms)
am
plit
ude (V
)
NL
LD+
LD-
Wave V Latency
Wave A Latency
V-A Slope The abnormal BioMAP children have delayed latencies and shallow slope
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How is the BioMAP test performed?
•Child awake sitting quietly in comfortable chair
•Watching favorite video; eyes open is OK
•Soundtrack of video played on low volume; audible to left ear
•BioMAP stimulus /da/ delivered into right ear; insert phone
•Test takes about 20 minutes
•One channel of ABR is collected
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How is the BioMAP test performed?
•One channel recording
•Cz = Channel 1, Input 1
•Right Ear = plugged into “ground” on Nav Pro
•Left Ear = Channel 1, Input 2 (true ground in this recording)
Electrode setup:
•Electrode switching = ON
With electrode switching “on” the
right ear will be used as the inverting
electrode when the stimulus is in the
right ear.
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•Collect 3 identical trials of 2000 sweeps
TRIAL 1
TRIAL 2
TRAIL 3
•Average the 3 trials together
AVERAGE
•Mark V and A, using normative wave template as a guide
TEMPLATE V
A O F E D
C
V
A
How is the BioMAP test performed?
Collection process:
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How is the BioMAP test analyzed?
Once the V and A on the response are labeled, the computer does the rest of the analysis.
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BioMAP Report
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Recent developments
A recently completed study at Northwestern
University has shown that the norms for
children age 5 are identical to the norms
previously collected on children in the 8-12 year
old range.
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Recent developments
Time (ms)
-0.3
-0.2
-0.1
0
0.1
0.2
0 10 20 30 40 50 60
3yo
4yo
5yo
8-12yo
V
A
C
D
E F
O
Am
plit
ude (
µV)
So the norms currently available for BioMAP can be used
for children from 5-12 years of age. 3-4 year olds show
some differences that are still being investigated.
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•Brainstem response reflects the acoustic characteristics of speech with remarkable fidelity. •Measures of latency and FFT amplitude can be assessed. •Normal perception depends on accurate timing of brainstem neurons.
SUMMARY Neural representation of speech in the brainstem
BioMAP Theory
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•These kids are the ones that show improved test scores on behavioral tests after intensive auditory training.
Quick Summary
•BioMAP is an ABR to a speech stimulus.
•30% of kids with auditory-based learning problems aged 8-12 years have poor BioMAP responses, confirming a physiologic basis for at least some of their learning problems.
•These kids also typically show an improved BioMAP response after auditory training.
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References
•Bio-logic:
www.natus.com
•BioMAP: http://www.communication.northwestern.edu/brainvolts/list/