acclimatization hi idhearing aids
TRANSCRIPT
Acclimatization Acclimatization to
h i idhearing aids
Piers Dawes, D.Phil,Audiology and Deafness Research Group
School of Psychological SciencesUniversity of Manchester UKUniversity of Manchester, UK
Supported by Starkey Hearing Research Centre
1
k• Background– Auditory plasticityy p y– Hearing aid plasticity
• Hearing aid acclimatization study
2
Auditory plasticityAuditory plasticity
l l• Adult animals– Plasticity was underestimatedy m– Passive exposure plasticity
Stimuli must be behaviourally relevant– Stimuli must be behaviourally relevant
3
Polley et al (2006)Polley et al. (2006)
4
Adult auditory plasticityAdult auditory plasticity
• Site is uncertain– connectivityy
M h i i i• Mechanism is uncertain– Role of attention
5
Adult auditory plasticityAdult auditory plasticity
l l l• Plasticity occurs in adult animals• Stimuli must be behaviourally relevantStimuli must be behaviourally relevant• Import role for attention• Very specific to aspects of stimulus
6
Hearing aid related plasticityHearing aid-related plasticity
l l l• Auditory plasticity is possible in adults• Stimulus is behaviourally relevant Stimulus is behaviourally relevant • Specific to aspects of stimulus• Mechanism/site unknown
Human model of adult auditory lplasticity
Clinical and research relevanceClinical and research relevance7
Hearing aid modelHearing aid model
D i ti l ti h Deprivation plastic changes
Restoration of input secondary changesRestoration of input secondary changes
8
From Munro (2008)
9
Speech identificationSpeech identificationno hearing aid hearing aid
75
80
corr
ect
no hearing aid hearing aid
Hi h presentati n level
65
70
Perc
ent
c High presentation level (69 dB SPL)
0 6 12Time since hearing aid fitting (weeks)
80ct
60
70
rcen
t co
rre
Low presentation level (55 dB SPL)
50
0 6 12Time since hearing aid fitting (weeks)
Per
10
Munro & Lutman, JASA, 2003, 114, 484-495
Electrophysiology: ABRElectrophysiology: ABR
11
Munro et al, NeuroReport, 2007, 18,1871-4
Electrophysiology: Cortical ERPsElectrophysiology: Cortical ERPs
l l h l l • Single adult with unilateral aid• Low and high frequency tones over a Low and high frequency tones over a
range of presentation levels
• Amplitude of mp tu of N1-P2 complex
Gatehouse S Robinson K (1996) Acclimatization to monaural hearing aid fitting effects on loudness functions and preliminary
12
Gatehouse, S., Robinson, K. (1996). Acclimatization to monaural hearing aid fitting- effects on loudness functions and preliminary evidence for parallel electrophysiological and behavioural effects. In B. Kollmeier (Ed.), Psychoacoustics, speech and hearing aids (pp.
319-330). Singapore: World Scientific
Cortical ERPs con’tCortical ERPs con t
N diff b t t l • No difference between ears at low frequencies where the hearing aid
id d lifi i provided no amplification
• High frequency tones resulted in a larger response in the fitted ear at high larger response in the fitted ear at high presentation levels
13
Previous acclimatization researchPrevious acclimatization research
l l h l l • Perceptual and electrophysiological evidence
Ch ifi t • Changes are specific to frequencies/intensities where hearing q gaid alters input
14
Previous acclimatization researchPrevious acclimatization research
ff • Inconsistent evidence; differences in– Participants: mix of new and experiencedp m f p– Stimulus: not well controlled
Measures: reliability and validity– Measures: reliability and validity
• Variability in outcomes; some people show acclimatization, others do notshow acclimatization, others do not
15
Starkey acclimatization study• Relationship between perception &
Starkey acclimatization studyp p p
physiology and real life benefit• When to measure benefit?• When to measure benefit?• How does the acclimatization process
differ for two versus one hearing aid?• Can you predict who will show the biggest Can you predict who will show the biggest
changes over time? bl d/ • Is it possible to increase rate and/or
extent of benefit?
16
Participants• 3 participant groups
– New Unilateral (N = 25)New Unilateral (N = 25)– New Bilateral (N = 17)
E i d (N 17)– Experienced (N = 17)Mean age ~70 yrsMean HL ~55 dB HL (new); ~65 dB HL (controls) (2-8 kHz)65 dB HL (controls) (2 8 kHz)
• Two test occasions: ( )– Fitting (T1)
– After 12 weeks use (T2)( )
17
StimulationStimulation
Hearing aid• circuitry (all same)• gain (real ear measures)• gain (real-ear measures)• usage (data logging)g gg g• quality of use (input level)
18
Measurement• Aids in sound field (not headphones)
M f /i i i h • Measures tap freqs/intensities where aids are expected to make a changep g
• Real-life relevance (SRM and listening effort)effort)
• Predictors of acclimatization– neural integrity (RT, WM, Age) – stimulation (Gain HA use input level) stimulation (Gain, HA use, input level) – initial deprivation (HL)
19
Measures
Behavioural measures: Speech in noise
Measures
Behavioural measures: Speech in noise, loudness balancing, Spatial release from masking, listening effortg, g
Electrophysiological measures: Acoustic Electrophysiological measures: Acoustic reflex, click-ABR, FFR, cortical ERPs, ERP measure of plasticityERP measure of plasticity
Real-world benefit: Spatial Speech and Real-world benefit: Spatial, Speech and Qualities of Hearing questionnaire
20
Measures
Behavioural measures: Speech in noise
Measures
Behavioural measures: Speech in noise, loudness balancing, Spatial release from masking, listening effortg, g
Electrophysiological measures: Acoustic Electrophysiological measures: Acoustic reflex, click-ABR, FFR, cortical ERPs, ERP measure of plasticityERP measure of plasticity
Real-world benefit: Spatial Speech and Real-world benefit: Spatial, Speech and Qualities of Hearing questionnaire
21
S ti l S h d Q liti f Spatial, Speech and Qualities of Hearing QuestionnaireHearing Questionnaire
• Report change in ability during study Report change in ability during study period
G h & N bl ( 004)
22
Gatehouse & Noble, (2004)
Spatial Speech and Qualities of Spatial, Speech and Qualities of Hearing Questionnaireg Q
30.00
40.00
10 00
20.00
0.00
10.00
Speech (20) Spatial (20) Quality (20) Effort (10) Total (70)
-20.00
-10.00
• New users report improvement
23
Speech recognitionSpeech recognition
h• Speech-in-noise– Four Alternative Auditory Feature test F y F
(FAAF; Foster & Haggard, 1987)
– T1 and T2
24
THOUGHTTHOUGHTO GFOUGHT
TAUGHTTAUGHTCAUGHTCAUGHT
2525
Speech recognitionSpeech recognition
Adaptive SNRp– SNR required for 50% correct– Normally aided configuration and unaidedNormally aided configuration and unaided– Change in 50% SNR between T1 and T2
26
Speech in noiseSpeech-in-noiseUnaided AidedAided
Better
NS trend for greater improvement for new users
27
Speech in noiseSpeech-in-noiseAidedU id d AidedUnaided
r = -.45, p = .04r = .13, p = .57
28
Speech in noise summarySpeech in noise summary
• Evidence of acclimatizationP t d d t t f • Part dependent on amount of hearing aid usehearing aid use
29
Click-ABRClick ABR
New Unilateral Experienced users New Unilateral n = 8
30
pn = 10
Cortical ERPsCortical ERPs3 kHz
65
75
85
d d d d
85
Aided Unaided T1 = dark green T2 = light green
31
T1 = dark green T2 = light green
Electrophysiology summaryElectrophysiology summary
l*Tentative results*• ABR: No acclimatization effect (by ABR: No acclimatization effect (by
12wks)C ti l ERP d i ti ff t f • Cortical ERP: deprivation effect for unaided ear
Acclimatizati n effects at level f Acclimatization effects at level of cortex
32
Further analysisFurther analysis
h l EE• Behavioural and EEG• Predictors of changePredictors of change
– Gain, HA use, initial HL, cognitiveU il l Bil l • Unilateral vs Bilateral
33
SummarySummary• Users report improvement over timeUsers report improvement over time• Perceptual and electrophysiological
evidence of acclimatizationevidence of acclimatization• Improvement in SIN over time• Consistent hearing aid use associated
with greater acclimatization, increased gbenefit
Clinical conclusionsClinical conclusions
1. Consistent hearing aid use greater acclimatization, increased benefitacclimatization, increased benefit
2 All ti f li ti ti b f 2. Allow time for acclimatization before measuring benefit
AcknowledgementsgCollaborators
Kevin Munro, Sridhar Kalluri, Brent Edwards, Harvey Abrams
ParticipantsWithington Community Hospital
T ff d G l H it lTrafford General HospitalStepping Hill Hospital
Technical supportKeith WilbrahamKeith Wilbraham
Starkey HRC who funded the studyStarkey HRC who funded the study
3636
