Mild hearing loss is serious business l.jpg
This presentation is the property of its rightful owner.
Sponsored Links
1 / 123

Mild Hearing Loss is Serious Business PowerPoint PPT Presentation


  • 300 Views
  • Updated On :
  • Presentation posted in: General

Mild Hearing Loss is Serious Business. Harvey Dillon Sharon Cameron, Teresa Ching, Helen Glyde, Gitte Keidser, David Hartley, Jorge Mejia NAL, The Hearing CRC IHCON, 2010. Slides on the NAL web site: www.nal.gov.au. What is mild hearing loss?.

Download Presentation

Mild Hearing Loss is Serious Business

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Mild hearing loss is serious business l.jpg

Mild Hearing Loss is Serious Business

Harvey Dillon

Sharon Cameron, Teresa Ching, Helen Glyde, Gitte Keidser, David Hartley, Jorge Mejia

NAL, The Hearing CRC

IHCON, 2010


Slide2 l.jpg

Slides on the NAL web site:

www.nal.gov.au


What is mild hearing loss l.jpg

What is mild hearing loss?

  • Four-frequency average (500, 1000, 2000, 4000 Hz) hearing loss in better ear between 20 and 40 dB HL

  • Self-reported disability or handicap within a certain range

  • SRT in noise loss of between 3 and 6 dB


4fahl or 3fahl l.jpg

4FAHL or 3FAHL?


How prevalent is mild hearing loss l.jpg

How prevalent is mild hearing loss?


How prevalent is mild hearing loss6 l.jpg

How prevalent is mild hearing loss?

  • Davis (1995): 16% of adult population

  • Wilson (1990): 18% of adult population

  • Hartley et al (in press): 34% of people aged > 50 years


Blue mountains 4fahl better ear l.jpg

Blue Mountains 4FAHL better ear

Hartley et al (in press)


Aging population australia l.jpg

Aging population - Australia


Population aging worldwide l.jpg

Population aging, worldwide


Mild losses for study l.jpg

Mild losses for study

~ Minimum loss eligible for government benefits

Mild loss (4FA=29 dB)

Mild-mod loss (4FA=39 dB)

~ Median loss newly fitted in Australia


Mild losses for study12 l.jpg

Mild losses for study

4FA HL

Mild 9 dB

Mild-mod 39 dB

Moderate 49 dB

Mod-Sev 59 dB

Severe 69 dB


How common is hearing aid use amongst those with mild hearing loss l.jpg

How common is hearing aid use amongst those with mild hearing loss?


Penetration by hearing loss l.jpg

Penetration by hearing loss

  • Penetration as a function of hearing loss

    • Davis (1995)

    • Wilson et al (1998)

    • Hartley et al (in Press)

    • Kochkin

consistent


Aid ownership by hearing loss blue mountains population 55 years l.jpg

Aid ownership by hearing lossBlue Mountains Population >55 years

Hartley et al (in Press)


What are the characteristics of mild hearing loss l.jpg

What are the characteristics of mild hearing loss?


Characteristics of mild loss l.jpg

Characteristics of mild loss

  • Threshold elevation √

  • Loss of OHC/OAE

  • Loss of frequency resolution – TEN, PTC, FRI

  • Loss of temporal (envelope) resolution

  • Loss of fine temporal information

  • Loss of spatial processing

  • Loss of SRT in noise

  • Increased disability and handicap


Loss of active process in cochlear ohc and oae l.jpg

Loss of active process in cochlear:OHC and OAE


Loss of frequency resolution l.jpg

FRI

A

A

f

f

Ching & Dillon (unpublished data)

Loss of frequency resolution


Frequency resolution l.jpg

Frequency resolution


Loss of temporal resolution l.jpg

A

TRI

t

t

Loss of temporal resolution


Temporal resolution l.jpg

Temporal resolution

Ching & Dillon (unpublished data)


Loss of fine temporal information l.jpg

Loss of fine temporal information

  • 20 synapses per IHC

  • Synapse loss or IHC loss  reduced averaging  temporal jitter

Inspiration:

  • Bodian, Lieberman, Moore, Pichora-Fuller, Spoendlin,


A digression into normal hearing l.jpg

A digression into “normal” hearing


Spatial processing disorder l.jpg

Spatial Processing Disorder

Speech

Sharon Cameron

Noise

Noise

Noise

Noise

26


Listening in spatialised noise sentences lisn s conditions l.jpg

Listening in Spatialised Noise - Sentences(LiSN-S) Conditions

Total Advantage

Talker Advantage

Spatial Advantage

Same voices

Different voices

Same

direction

Low Cue

Different

directions

High Cue

Cameron & Dillon (2009)


Lisn s diagnostic screen l.jpg

LiSN-S Diagnostic Screen


Spatial advantage spatial release from masking l.jpg

Spatial Advantage(≡ Spatial Release from Masking)

Nth America

Australia

Better


Spatial advantage l.jpg

Spatial Advantage

Better


Results profile spatial processing disorder l.jpg

Results profile: spatial processing disorder


Spatial processing remediation pre vs post n 9 l.jpg

Spatial processing remediation Pre vs. Post (n=9)

LC SRT - p = 0.158

Talker Advantage - p = 0.981

HC SRT - p = 0.0002

Spatial Advantage - p = 0.0002

Total Advantage - p = 0.001


Application to people with hearing loss l.jpg

Application to people with hearing loss


Spatial hearing loss in hearing impaired people lisn s prescribed gain amplifier l.jpg

Spatial hearing loss in hearing-impaired people:LiSN-S Prescribed Gain Amplifier


Deficit in srt n with hearing loss l.jpg

Deficit in SRTn with hearing loss

R = -0.87

P = 0.000006

Cameron, Glyde & Dillon, unpublished data)


Cause of deficit in srt n l.jpg

Cause of deficit in SRTn

R = -0.86

P = 0.00001

Cameron, Glyde & Dillon, unpublished data)


Talker advantage deficit versus age l.jpg

Talker advantage deficit versus age

Cameron, Glyde & Dillon, unpublished data)


Binaural processing l.jpg

ILD

ITD

SO / IC / A1

~

Sensorineural

hearing loss

CN

CN

Binaural processing

Executive

control

CAPD

x

x

ILD

ITD

R

L


Loss of snr in understanding speech l.jpg

Loss of SNR in understanding speech

“Basic” loss of 0.6 dB per 10 dB of loss

+

Loss of Spatial release from masking of 2.3 dB per 10 dB of loss

+

Loss of Talker cue release from masking of 0.5 dB per 10 years of age


Loss of srt in noise l.jpg

1 dB / 10 dB

1.8 dB / 10 dB

Loss of SRT in noise

Commonly 1.5 dB increase in SNR per 10 dB of hearing loss

SNR = -4 dB

Carter, Zhou & Dillon, unpublished data)


Should mild hearing loss interfere with speech perception l.jpg

Should mild hearing loss interfere with speech perception?


Speech and noise levels l.jpg

SNR

Speech and noise levels

Source: Pearsons, Bennett and Fidell (1977)


Calculation of sii l.jpg

Calculation of SII

Noise = 60 dBA Speech = 64 dBA SIInh=0.65 SIIhi=0.46


Effective audibility l.jpg

20

40

60

80

100

Effective audibility


Transfer function sii percent correct l.jpg

Transfer functionSII  Percent correct


Mild losses for study45 l.jpg

Mild losses for study

Mild loss (4FA=29 dB)

Mild-mod loss (4FA=39 dB)


Predicted speech intelligibility l.jpg

Predicted speech intelligibility

Greatest problems in noisy places !!


Predicted variation of srt n with hearing loss l.jpg

Predicted variation of SRTn with hearing loss

Modified SII model predicts only 0.4 dB loss per 10 dB of hearing loss

Speech

level


Modification of sii l.jpg

Modification of SII

  • Assume normal hearers get 6 dB advantage from spatial separation of speech and noise

  • Assume hearing impaired listeners lose spatial advantage at a rate of 1.3 dB per 10 dB of loss (above SII predictions)

     total loss of SNR is 1.7 dB per 10 dB of loss


Calculation of intelligibility l.jpg

Calculation of intelligibility

Speech spectrum

Sensation Level

Effective audibility

Noise spectrum

SII

(Information received)

Percent correct

Max

Importance function

Threshold


Do hearing aids help people with mild hearing loss l.jpg

current

^

Do hearing aids help people with mild hearing loss?


Benefit of hearing aids l.jpg

Benefit of hearing aids

Predict increase in speech intelligibility

with

the modified Speech Intelligibility Index


Calculation of aided benefit l.jpg

Calculation of aided benefit

Noise = 50 dBA

Speech = 58 dBA


Speech intelligibility mild loss l.jpg

Speech intelligibility (mild loss)

  • Hearing aid “helps” in quiet places

  • Tiny additional benefit from directivity

Conditions:

DI = 3 dB when REIG > 3 dB

n.h. spatial adv = 6 dB

∆SNR re n.h. = -3.7 dB


Speech intelligibility mild moderate loss l.jpg

Speech intelligibility (mild-moderate loss)

  • Hearing aid “helps” in quiet places

  • Tiny additional benefit from directivity

Conditions:

DI = 3 dB when REIG > 3 dB

n.h. spatial adv = 6 dB

∆SNR re n.h. = -5.1 dB


Speech intelligibility moderate loss l.jpg

Speech intelligibility (moderate loss)

Conditions:

DI = 3 dB when REIG > 3 dB

n.h. spatial adv = 6 dB

∆SNR re n.h. = -6.5 dB


Speech intelligibility moderate severe loss l.jpg

Speech intelligibility (moderate-severe loss)

Conditions:

DI = 3 dB when REIG > 3 dB

n.h. spatial adv = 6 dB

∆SNR re n.h. = -7.7 dB


Speech intelligibility severe loss l.jpg

Speech intelligibility (severe loss)

Conditions:

DI = 3 dB when REIG > 3 dB

n.h. spatial adv = 6 dB

∆SNR loss re n.h. = -9 dB


Summary of benefit versus hl l.jpg

Summary of benefit versus HL

Background noise level

40 dB A

60 dB A

80 dB A


Why don t directional microphones help more in noise l.jpg

Why don’t directional microphones help more in noise?

(and adaptive noise reduction)


1 impact of open fittings on directivity l.jpg

1. Impact of open fittings on directivity

Directional

Omni-directional

DI = 3 dB  1.5 dB

DI = 10 dB  5 dB


Frequency range of directional mic mild loss l.jpg

50

60

70

80

Frequency range of directional mic (mild loss)

Effect of dynamic noise reduction on directional mic


Effect of aiding at 60 dba mild loss l.jpg

Effect of aiding at 60 dBA (mild loss)

Noise = 60 dBA

Speech = 64 dBA


Effect of aiding at 80 dba mild loss l.jpg

Effect of aiding at 80 dBA (mild loss)

Noise = 80 dBA

Speech = 76 dBA


2 impact of reverberation on directivity and vice versa l.jpg

2.Impact of reverberation on directivity (and vice versa)

Total

Reverberant

Direct


Slide65 l.jpg

  • Impact of reverberation on directivity (and vice versa)

Total

Direct

Reverberant


Benefit of directional microphones l.jpg

Benefit of directional microphones

Benefit affected by:

  • Directivity pattern of microphone

  • Distance and direction of talker and noise sources

  • Acoustics of the room

  • Frequency range over which the hearing aid is directional

  • Frequency range over which the wearable has usable hearing

  • Nothing else

(OK, Measurement error!!)


Conclusion of acoustic analysis l.jpg

Conclusion of acoustic analysis

  • People with mild loss need help in noisy places

  • Hearing aids increase the speech information available mostly in quiet places!

  • Mics directional only where there is gain

    • high frequencies and lower levels

    • Where audibility is limited by threshold, not noise


Slide68 l.jpg

So, objective benefit questionable, and increasing with degree of loss, but …….

What do hearing aid users say ?


Experimental evaluation of self reported benefit l.jpg

Experimental evaluation of self-reported benefit

  • 400 clients sampled from national database

    • 41,521 new clients fitted Feb to Sept, 2004

  • Audiometric and other details obtained from clients’ files

  • Questionnaire sent to clients 5 to 12 months after fitting

    • International Outcome Inventory for Hearing Aids

    • Plus 6 purpose-designed questions

  • Non-responders followed up by phone or additional mail to get a high response rate (effectively 86%)


Hearing loss distribution l.jpg

Hearing loss distribution

Sample distribution

Population distribution


Usage of hearing aids l.jpg

Usage of hearing aids


Factor analysis of questionnaire l.jpg

Composite benefit

Composite difficulty

Vision

Factor analysis of questionnaire

International Outcomes Inventory

for

Hearing Aids


Effect of hearing loss on benefit l.jpg

Effect of hearing loss on benefit


Slide74 l.jpg

If hearing loss does not determine benefit, then what does?


W ishes a nd n eeds t ool l.jpg

Wishes And Needs Tool

  • How strongly did you want to get hearing aids?

    Wanted it very much

    Wanted it quite a lot

    Wanted it moderately

    Wanted it slightly

     Did not want it

  • Overall how much difficulty do you have hearing when you are not wearing your hearing aids?

    Very much difficulty

    Quite a lot of difficulty

    Moderate difficulty

    Slight difficulty

    No difficulty


Difficulty hearing unaided and wish to get hearing aids l.jpg

Very much

Not at all

Want hearing aids

Difficulty hearing unaided and wish to get hearing aids

Unaided difficulty related to wish to get hearing aids


Need increases with hearing loss l.jpg

Need increases with hearing loss


Benefit versus need strength l.jpg

Benefit versus need strength


Why don t more people with mild hearing loss even try hearing aids l.jpg

Why don’t more people with mild hearing loss even try hearing aids?


Factors affecting benefit experienced and hence the reports of others l.jpg

Factors affecting benefit experienced(and hence the reports of others)

  • Degree of pure-tone loss

  • Self-reported disability and handicap

  • Acceptable Noise Level

  • Stigma / cosmetic concern

  • Manipulation and management

  • Age

  • Tinnitus

  • Personality ….


Personality l.jpg

Personality

People more likely to acquire hearing aids are:

  • Open

  • Non-obsessive

  • Non-neurotic

  • Internal locus of control

    People more likely to report benefit are:

  • Extroverted

  • Agreeable


Health belief model l.jpg

Health Belief Model

People act rationally, in their best interests, based on their beliefs

Weighing up of beliefs for and against a health decision

Do I have

a problem?

Is it serious

enough for me to

want to remove it?

Is there a

solution

that works?

Disadvantages

Advantages

What are the

disadvantages

of the solution?

“My hearing loss is not bad enough to need them” (Kochkin, 1993)


Motivation comes from l.jpg

Self-image

Expect benefit

Try them

Expect to manage them

$ Cost OK

Motivation comes from ….

Acknowledge loss

Experience difficulty

Experience handicap


Health belief model84 l.jpg

Health belief model

Difficulties experienced: frequency, severity

Self-image

Hearing aid

effectiveness

External

image

Ability to

manage

Hearing

loss

Cost

Incon-venience


Health belief model85 l.jpg

Self-image

External

image

Hearing aid

effectiveness

Ability to

manage

Difficulties experienced: frequency, severity

Cost

Inconven-ience

Hearing

loss

Health belief model


Health belief model86 l.jpg

Difficulties experienced: frequency, severity

Self-image

Hearing aid

effectiveness

External

image

Ability to

manage

Hearing

loss

Cost

Inconven-ience

Health belief model


How can the balance of benefits to disadvantages be improved l.jpg

How can the balance of benefits to disadvantages be improved?


Improving advantages and removing disadvantages l.jpg

Cost

Working better

in noise

Improving advantages and removing disadvantages

  • WDRC

  • Slim-tube, miniaturization

  • Feedback cancellation

  • Low-level expansion

  • Re-chargeable batteries

  • Auto telecoil

  • Frequency lowering

  • Bandwidth extension

  • Trainable responses

  • Adaptive noise reduction

  • Transient noise reduction

  • Directional microphones

Problem 1

Solution 1

Problem 2

Solution 2

Problem 3

Solution 3


Speech intelligibility in noise l.jpg

Speech intelligibility in noise


Binaural processing super directional microphone mejia et al 2007 l.jpg

Binaural-Processing Super-directional Microphone (Mejia et al., 2007)

Rear- directional array

W1

W2

Q1

Q2

Binaural beamformer

Q3

Q4

W3

W4

Masking threshold

Main directional signal

d = 3 ms delay

(Precedence effect)

K

K

Subsidiary signal

Z-d

HRTFL

HRTFR

Cross-fading process

DOA- reconstruction

Lout

Rout

Outputs with spatial reconstruction


Super directional microphones l.jpg

Super-directional microphones


Speech reception threshold in noise reverberant room crit dist 0 4m radius 1 m l.jpg

Speech reception threshold in noiseReverberant room: crit dist = 0.4m, radius = 1 m

Mejia and Johnson, unpublished data


Slide93 l.jpg

Linked binaural hearing aid technology

Female

talker

Male

talker

Listener

Children

playing

Hearing Aid


Blind source separation binaural noise reduction l.jpg

Blind-source separation binaural noise reduction

h.i.

gain most from directivity

n.h. benefit from re-insertion of spatial cues

Implication: People with mild or moderate hearing loss were not making much use of spatial cues.


Effect of super directivity mild loss l.jpg

Effect of super-directivity (mild loss)

  • Super-directional mic not directional at all over a broader and broader range as noise levels rise

Conditions:

DI = 6 dB when REIG > 3 dB

n.h. spatial adv = 6 dB

∆SNR re n.h. = -3.7 dB


So super directivity alone is no use l.jpg

So super-directivity alone is no use ……..


What if we could achieve directivity at low frequencies l.jpg

What if we could achieve directivity at low frequencies?


Effect of low frequency directivity mild loss l.jpg

Effect of low-frequency directivity (mild loss)

  • Now directional over entire frequency range in noisy places

Conditions:

DI = 3 dB when REIG ≥ 0 dB

n.h. spatial adv = 6 dB

∆SNR re n.h. = -3.7 dB


Occlusion with closed molds l.jpg

Occlusion with closed molds

Vent or leak transmission in


Active occlusion reduction l.jpg

Active Occlusion Reduction

Hear

Aid

C

+

Σ

-

A

B


Active occlusion reduction101 l.jpg

Active occlusion reduction

Mejia, Dillon, & Fisher (2008)


In combination l.jpg

In combination?

Active occlusion reduction

(closed mold)

Super-directivity

+

= ?


Low frequency super directivity mild loss l.jpg

Low-frequency super-directivity (mild loss)

  • Super-directivity over entire frequency range

  •  super-normal hearing

Conditions:

DI = 6 dB when REIG ≥ 0 dB

n.h. spatial adv = 6 dB

∆SNR re n.h. = -3.7 dB


Low frequency super directivity mild moderate loss l.jpg

Low-frequency super-directivity (mild-moderate loss)

  • Super-normal hearing for the median hearing aid wearer

Conditions:

DI = 6 dB when REIG ≥ 0 dB

n.h. spatial adv = 6 dB

∆SNR re n.h. = -5.1 dB


Low frequency super directivity moderate loss 4fa 49 8 db hl l.jpg

Low-frequency super-directivity (moderate loss, 4FA = 49.8 dB HL)

  • Super-normal hearing in very noisy places for even a moderate-severe loss

Conditions:

DI = 6 dB when REIG ≥ 0 dB

n.h. spatial adv = 6 dB

∆SNR re n.h. = -6.5 dB


Adaptive noise reduction l.jpg

Adaptive noise reduction

  • Gain dependent on SNR correct in principle, but room for improvement:

    • Gain reduction can reduce directional mic effectiveness

    • No point in reducing noise below threshold

    • Gain increase where SNR is best is just as important


Slide107 l.jpg

Cost

Jump to summary


Self fitting hearing aid l.jpg

Self-fitting hearing aid

NAL-NL2 Prescription Formula

Real-ear to coupler difference

Automatic

Adjust Hearing Aid

Audiometer

Plus trainability

Australia, USA: 1 audiologist per 10,000 people

Developing countries: 1 audiologist per 500,000 people, to 1 per 6,000,000


Automatic versus manual audiometry l.jpg

Automatic versus manual audiometry

1 kHz


Test retest standard deviations l.jpg

Test-retest standard deviations

RECD

Auto Aud

Adjust

NAL-NL2

Manual audiometry (5 dB Hughson-Westlake)

Automatic audiometry (2 dB final step size)


Real ear to dial difference inter subject standard deviations l.jpg

Real-Ear to Dial Difference:Inter-subject standard deviations


Real ear to dial difference inter subject standard deviations112 l.jpg

Real-Ear to Dial Difference:Inter-subject standard deviations

Insert

Saunders & Morgan

Valente et al

Hawkins et al

Supra-aural

Valente et al

Hawkins etal


Trainable hearing aids l.jpg

CR

Gain

CT

Trainable Hearing Aids


In summary l.jpg

In summary…


In summary115 l.jpg

In summary

very

How prevalent is mild hearing loss?

How common is hearing aid use amongst those with mild hearing loss?

not very

many, including spatial hearing loss

What are the characteristics of mild hearing loss?

Is mild hearing loss a problem to people?

yes, in noise

Do hearing aids help people with mild hearing loss?

only in quiet places

….. expected benefit too small re need

Why don’t more people with mild hearing loss even try hearing aids?

closed-ear, binaural processing

How can hearing aids provide greater benefit where it is most needed?


Messages for l.jpg

Messages for ….

  • Public health authorities:

    • Increase hearing awareness (prevention, rehabilitation)

    • Increase hearing screening opportunities


Messages for117 l.jpg

  • Clinicians:

    • Discern primary reasons why unmotivated clients are unmotivated

    • Provide information to change unrealistic beliefs

    • Understand and diagnose the fundamental problem that clients are presenting with SRT loss

Messages for ….


Messages for118 l.jpg

Messages for ….

  • Researchers:

    • Better understanding of the components and causes of SNR loss

    • Prescription procedures for adaptive noise suppression

      • Time constants

      • Relationship with thresholds

      • Relationship with noise spectrum and level


Messages for119 l.jpg

Messages for ….

  • Manufacturers:

    • Achieve better performance in noise

      •  Binaural processing

      •  Closed fittings

      •  Wireless

      •  Smarter adaptive noise suppression


Hearing aids of the future l.jpg

Hearing aids of the future

?

  • Convergence:

  • hearing aid/enhancer,

  • phone interface,

  • hearing protector,

  • computer interface (in and out),

  • music player,

  • GPS interface


Thanks for listening l.jpg

Thanks for listening

For the slides from this talk ..…

www.nal.gov.au


Amplification and directivity l.jpg

Amplification and directivity

50 dBA

80 dBA

Unaided

Aided


  • Login