bera or abr

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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• 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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• 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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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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• 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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• 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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• 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 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 + 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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Copyright 2006 Courtesy of Auditory Neuroscience Lab Northwestern University, Nina Kraus, Director

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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•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


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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Copyright 2006 Courtesy of Auditory Neuroscience Lab Northwestern University, Nina Kraus, Director

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/

http://www.natus.com/

http://www.communication.northwestern.edu/brainvolts/list/

bera or abr

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