The audiometric threshold: measured in-situ, automated, and by the hearing aid

Gitte Keidser, Harvey Dillon, Anna O’Brien, Dan Zhou, Lyndal Carter, Ingrid Yeend, and Lisa Hartley

National Acoustic Laboratories

AHS June 2010Lake Como

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Background

Conventional audiometry

Most modern hearing aids have on-board generators that produce pure tones in-situ audiometry

Low-cost tests of hearing over the telephone or internet in demand automated audiometry

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Self-fitting hearing aid (concept)

Audiometer

Prescription Formula

Adjust Hearing Aid

Real-ear to coupler difference

Automatic

Plus trainability

meet high demands in developing countries where services are scarce

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Questions Is in-situ audiometry valid and reliable?

What is the effect of using different couplings (open vs closed domes) on in-situ threshold measurements?

Is automated audiometry valid and reliable?

National Acoustic Laboratories, Sydney, Australia Keidser et al.

In-situ audiometry 24 participants with

known sensorineural hearing loss

Measurements (twice) Conventional audiometry

(insert) Manual in-situ audiometry

(open and closed instant tips)

REDD (insert, open, closed)

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Thresholds in dB HL

(Test-retest, p = 0.69)

National Acoustic Laboratories, Sydney, Australia Keidser et al.

REDD values

p < 0.0000001

(Test-retest, p = 0.58)

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Thresholds in dB SPL

dB SPL = dB HL + REDD

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Reliability

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Reliability

Supra-aural

Valente et al

Hawkins et al

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Reliability

Supra-aural

Valente et al

Hawkins et al

Insert

Saunders & Morgan

Valente et al

Hawkins et al

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Automated audiometry

23 participants (46 ears)

Threshold measurements at 0.25, 1, and 4 kHz Manually Automated, adaptive

procedure

AA01 AA02 AA03 AA04 AA05 AA06 AA07 AA08 AA09 AA11 AA12 AA13 AA14 AA15 AA16 AA17 AA18 AA19 AA20 AA21 AA22 AA23 AA24 AA01 AA02 AA03 AA04 AA05 AA06 AA07 AA08 AA09 AA11 AA12 AA13 AA14 AA15 AA16 AA17 AA18 AA19 AA20 AA21 AA22 AA23 AA24

250 1000 4000

Frequency (H z)

-10

0

10

20

30

40

50

60

70

80

Threshold (dB HL)

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Validity

National Acoustic Laboratories, Sydney, Australia Keidser et al.

ReliabilityManual audiometry (5 dB Hughson-Westlake)

Automatic audiometry (2 dB final step size)

Automated audiometry is at least as accurate as manual audiometry

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Conclusions Is in-situ audiometry valid and reliable?

corrections for coupling required (REDD)ambient noise is controlledopen tips more reliable than closed tips

Is automated audiometry valid and reliable?

Is automated in-situ audiometry valid and reliable?

Most likely

National Acoustic Laboratories, Sydney, Australia Keidser et al.

Acknowledgement

The in-situ audiometry study was partly sponsored by Siemens Instruments

The automated audiometry study was partly sponsored by Australian Hearing

The self-fitting hearing aid concept is now being further explored through the Hearing CRC

Thank you for listening!

For further information:www.nal.gov.au

www.hearingcrc.org

Gitte.keidser@nal.gov.au