Download Role of Auditory Steady State Response in Young Children

Role of Auditory Steady State Response in Young Children
  Rationale for application of ASSR in young children
  Brief historical overview   Principles of ASSR measurement
  Clinical advantages and disadvantages of ASSR
  Lingering questions about ASSR
  Additional clinical applications of ASSR
Limitation of Click-Evoked ABR:
Lack of Frequency-Specificity
Normal click
ABR
Abnormal or
no click
ABR
Estimation of Frequency-Specific Auditory Thresholds with Auditory Electrophysiology: An Essential Step in
Prescriptive Hearing Aid Fitting in Infants
Limitation of Tone Burst Evoked ABR in Severe-to-Profound Hearing Loss
8K
.50
dB HL
8K
.50
20
40
60
80
100
No ABR > 80 dB HL
AC
BC
Frequency in Hz
No ASSR > 120 dB HL
Frequency in Hz
Year 2007 JCIH Position Statement: Protocol for Evaluation for Hearing Loss
In Infants and Toddlers from Birth to 6 months
 
 
 
 
Child and family history
Evaluation of risk factors for congenital hearing loss
Parental report of infants responses to sound
Clinical observation of infants auditory behavior. Behavioral observation alone is not
adequate for determining whether hearing loss is present in this age group, and is not
adequate for the fitting of amplification devices.
  Audiological assessment
  Auditory brainstem response (ABR)
  Click-evoked ABR with rarefaction and condensation single-polarity stimulation if
there are risk factors for auditory neuropathy
  Frequency-specific ABR with air-conduction tone bursts
  Bone-conduction stimulation (as indicated)
  Otoacoustic emissions (distortion product or transient OAEs)
  Tympanometry with 1000 Hz probe tone
  Supplemental procedures, e.g.,
  Electrocochleography (ECochG)
  Auditory steady state response (ASSR)   Acoustic reflex measurement (for 1000 Hz probe tone)
Role of Auditory Steady State Response in Young Children
  Rationale for application of ASSR in young children
  Brief historical overview   Principles of ASSR measurement
  Clinical advantages and disadvantages of ASSR
  Lingering questions about ASSR
  Additional clinical applications of ASSR
Auditory Steady State Responses (ASSRs):
Selected Early Literature from the Australian Group
  Rickards & Clark. Steady-state evoked potentials to amplitude modulated tones.
 
 
 
 
 
In Evoked Potentials II. Boston: Butterworth, 1984.
Rickards et al. Auditory steady-state evoked responses in newborns. British
Journal of Audiology 28: 1994.
Rance, Rickards et al. The automated prediction of hearing thresholds in
sleeping subjects using steady state evoked potentials. Ear & Hearing 16: 1995.
Rance, Dowell, Rickards et al. Steady-state evoked potential and behavioral
hearing thresholds in a group of children with absent click-evoked ABRs. Ear &
Hearing 19: 1998.
Rance, Beer, Cone-Wesson et al. Clinical findings for a group of infants and
young children with auditory neuropathy. Ear & Hearing 20: 1999.
Rance & Briggs. Assessment of hearing in infants with moderate to profound
impairment: The Melbourne experience with auditory steady-state evoked
potential testing. Ann Otol Rhinol Laryngol 111: 2002
Auditory Steady State Responses (ASSRs):
Selected Early Literature from the Canadian Group
  Linden, Campbell, Hamel, Picton: Human auditory steady state evoked potentials
 
 
 
 
 
 
during sleep. Ear & Hearing 6: 1985.
Stapells, Makeig, Galambos. Auditory steady-state response threshold prediction
using phase coherence. EEG & Clin Neurophysiol 67: 1987.
Valdes, Perez-Abalo et al. Comparison of statistical indicators for the automatic
detection of 80 Hz auditory steady state responses. Ear & Hearing 18: 1997.
Picton et al. Objective evaluation of aided thresholds using auditory steady-state
responses. JAAA 9: 1998.
John & Picton. Human auditory steady-state responses to amplitude-modulated
tones: phase and latency measurements. Hearing Research 141: 2000.
John & Picton. MASTER: A Windows program for recording multiple auditory
steady-state reponses. Computer Methods and Programs in Biomedicine 61: 2000.
Dimitrijevic, John, van Roon, Picton. Human auditory steady-state responses to
tones independently modulated in both frequency and amplitude. Ear & Hearing
22: 2001.
AUDITORY STEADY STATE RESPONSE (ASSR):
Historical Perspective on Terminology
  Amplitude-modulation-following response (AMFR)
The Auditory Steady-State Response: A Book and > 400 Medline Hits (www.nlm.nih.gov)
  Envelope -following response (EFR)
  Frequency-following response (FFR)
  Steady state evoked response (SSER)
  Steady state evoked potential (SSEP)
  40 Hz response
  Auditory steady state response (ASSR)
Role of Auditory Steady State Response in Young Children
  Rationale for application of ASSR in young children
  Brief historical overview   Principles of ASSR measurement
  Clinical advantages and disadvantages of ASSR
  Lingering questions about ASSR
  Additional clinical applications of ASSR
Auditory Steady State Response (ASSR):
Clinical Devices
ASSR: General Measurement Principles
Anatomy & Physiology of ASSR: Generators
(Kuwada et al, 2002)
  An electrophysiological response, similar to ABR.
  Instrumentation includes:
  Insert earphones
  Surface electrodes
  Averaging computer
  Stimuli are pure tones (frequency specific, steady state
Slower modulation rates (< 80 Hz) = Cortical regions
signals) activating cochlea and CNS
  ASSR is generated by rapid modulation of carrier pure tone
amplitude (AM) or frequency (FM).
  Signal intensity can be as high as 120 dB HL
  ASSR phase or frequency is detected automatically (vs. visual
detection)
Faster modulation rates (> 80 Hz) = Brainstem ASSR Stimulation: Amplitude and Frequency Modulation Anatomy & Physiology of ABR vs. ASSR:
Neuronal Generator Types
Carrier frequency (pure tone) changes in intensity and/or frequency over time
  onset (ABR)
  offset
  onset-offset
  pauser
Frequency
Amplitude
  chopper
  inhibitory
  tonic (ASSR?)
100% AM
50% FM
ASSR: Graphic display in vector plot of EEG
samples at modulation frequency
B
c
b
a
A
C
ASSR (GSI Audera):
Significant phase coherence
Vector length (c) =
magnitude of activity
Vector angle (a) = phase
lag between stimulus
MF and EEG at MF
ASSR (GSI Audera):
No Response Condition
ASSR (GSI Audera): Test trials by frequencty
AUDITORY STEADY STATE RESPONSE (ASSR) IN INFANT HEARING ASSESSMENT AND MANAGEMENT:
Frequency-Specific Stimulation
ASSR (GSI Audera):
Estimated Audiogram
1000
2000
4000
500
EEG + ASSR
Modulated Stimuli Produce Frequency-Specific SteadyState Responses at the Modulation Frequency
BioLogic MASTER:
Four Stimuli Presented Simultaneously to One Ear
500 Hz
Carrier at 1 kHz
100% AM
81Hz modulation
frequency
Activation at 1 kHz region Steady-State response
of basilar membrane
at the modulation
frequency
1000 Hz
Activation at the carrier
frequency regions of the
basilar membrane
2000 Hz
ASSR at the modulation
frequencies
4000 Hz
81 Hz
Frequency Spectra – EEG & ASSR
Sound
Cochlea
Brain
Frequency Spectra – EEG & ASSR
Combined
Sound
Cochlea
Brain
ASSR Analysis:
Bio-logic MASTER II
The EEG is
converted into the
frequency domain
by FFT
FFT
EEG epoch x 16
Hz
The amplitude of the response to each
stimulus is measured at the unique
modulation rate of each carrier
frequency
AUDITORY STEADY STATE RESPONSE (ASSR) IN INFANT HEARING ASSESSMENT AND MANAGEMENT:
Recent Research on Multiple versus Single Stimuli
  Ishida & Stapells. Multiple-ASSR interactions in adults with
sensorineural hearing loss. International J Otolaryngology, 2012
  Studied effects of single versus multiple simultaneous stimuli on
the 80 Hz and 40 Hz ASSR in adults with normal hearing or SNHL
  Results showed:
 Decreased amplitudes for ASSRs for multiple versus single
stimuli in one ear
 For 40 Hz ASSR there were further decreases in amplitudes for
multiple stimuli in 2 ears versus 1 ear
 Effects were comparable for normal versus SNHL ears
 Multiple stimuli are of clinical value, but there are likely
situations where its more efficient to use single stimuli
AUDITORY STEADY STATE RESPONSE (ASSR) IN INFANT HEARING ASSESSMENT AND MANAGEMENT:
Automated Statistically-Based Analysis
AUDITORY STEADY STATE RESPONSE (ASSR) IN INFANT HEARING ASSESSMENT AND MANAGEMENT:
Automated Statistically-Based Analysis
Role of Auditory Steady State Response in Young Children
  Rationale for application of ASSR in young children
  Brief historical overview   Principles of ASSR measurement
  Clinical advantages and disadvantages of ASSR
  Lingering questions about ASSR
  Additional clinical applications of ASSR
Auditory Steady State Responses (ASSRs):
Pros and Cons for Clinical Use
  Advantages (Pros)
  Reasonably frequency specific stimuli
  Can be used for electrophysiological assessment of severe to
profound degree of hearing loss in infants and young children
  FDA-approved clinical devices available
  Automated analysis
  Potential disadvantages (Cons)
  Requires very quiet state of arousal
  Sedation or anesthesia is often necessary
  Limited anatomic site specificity   Analysis difficult with bone conduction stimulation A Major Advantage of ASSR: Estimating Auditory Thresholds
Beyond the Frequency and Intensity Limits of ABR
ASSR, ABR, and Pure Tone Audiometry:
Asking the clinically relevant question
Role of Auditory Steady State Response in Young Children
Not: Which frequency-specific electrophysiologic
technique is best … tone burst ABR or ASSR?
But: How does the ASSR technique complement
click and tone burst ABR techniques in the
infant test battery?
  Rationale for application of ASSR in young children
  Brief historical overview   Principles of ASSR measurement
  Clinical advantages and disadvantages of ASSR
  Lingering questions about ASSR
  Additional clinical applications of ASSR
ASSR: Clinical questions
  Are there maturational effects on ASSR from premature infants
 
 
 
 
 
 
through childhood?
What neuron populations and neurophysiologic principles are
important in understanding the ASSR?
Can ASSR be recorded from non-sedated patients?
What is the effect of sedation and anesthesia on ASSR?
How closely correlated are ASSR and pure tone hearing
thresholds?
Can ASSR be used in estimation of bone conduction auditory
thresholds?
Will the ASSR have neuro-diagnostic applications, e.g., detection
of retrocochlear dysfunction, dyslexia?
Role of Auditory Steady State Response in Young Children
  Rationale for application of ASSR in young children
  Brief historical overview   Principles of ASSR measurement
  Clinical advantages and disadvantages of ASSR
  Lingering questions about ASSR
  Additional clinical applications of ASSR
ASSR: Current and Potential Clinical Applications
  Frequency-specific estimation of auditory thresholds in
infants and young children
  Frequency-specific estimation of auditory thresholds in
selected adult populations (e.g., malingerers)
  Frequency specific estimation of hearing aid gain in infants
and young children with signals delivered via small speakers
  Electrophysiological confirmation of neural dysfunction in
certain clinical populations, e.g., dyslexia
  Differentiation of cochlear versus retrocochlear auditory
dysfunction
Thank You!
Questions?