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Relating hearing-aid gain settings to clinical outcome measures
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Christophe Micheyl , William S Woods , Joyce Rosenthal , Sridhar Kalluri , Peter Johannesen , José L. Blanco , Patricia Pérez-González , Enrique A Lopez-Poveda , Brent Edwards
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Starkey Hearing Research Center, Berkeley, CA
The setting of hearing-aid gains is an essential step in the fitting of multi-channel
hearing aids.
Here, we examine relationships between hearing-aid gains and perceived hearing-aid benefit.
Starkey Hearing Technologies, Eden Prairie, MN
Real-ear insertion gains (REIGs) and targets for speech (ISTS)
- On average, adjusted gains were lower than NAL-NL1 targets, and closer to
eStat targets
Right ear
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Left ear
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15
5
REIG (dB)
Gain settings can influence satisfaction with hearing-aids; in particular, ‘loud
sounds’ are a primary cause of user dissatisfaction (e.g., Kochkin, 2005).
Average (65 dB SPL)10
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10
Such variability made it possible to explore correlations between deviations from targets and
subjective measures of hearing aid outcomes.
Starting from NAL-NL1 targets, gains were
usually adjusted downward on the
first visit, based on participants’ feedback.
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20
15
- Absolute deviations from eStat targets were correlated with SSQ-B scores
10
5
Little change was made after 1 month.
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Loud (80 dB SPL)
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10
However…
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REIG (dB)
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Adjusted gains were often relatively close to
eStat targets (Starkey’s formula).
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15
10
5
0
0.25
0.5
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2
Frequency (kHz)
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8 0.25
0.5
1
2
Frequency (kHz)
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SSQ-B response matrix
(subjects x questions)
Speech
Spatial
Qualities
Naturalness
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Correlation coefficient*
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10
3
1
30
0
-1
-2
50
SSQ-B score
Subject
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40
-3
60
Subjects
N = 68, hearing-impaired individuals (audiograms below) were fitted bilaterally
with Starkey RIC312 hearing aids.
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100
120
0.25
0.5
1
2
Frequency (kHz)
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8
Protocol
*Coefficients for which p>0.05 are set to 0.
Participants’ evaluation of hearing aids
was usually positive (more warm colors)
Individual data
Mean +/- SD
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40
60
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4
100
0.25
0.5
1
2
Frequency (kHz)
4
8
3
2
1
-1
-10
-5
0
5
Deviation from eStat (500-8000 Hz)
49 questions on perceived benefit of hearing aids
Example:
Spatial
Qualities
0.2
7052
6622
0.1
6192
- answers to questionnaires depend on many factors: expectations with hearing aids; mood at time
of testing; level of engagement with the questionnaire; ability to remember, or imagine, listening situations such as those described in the questionnaire; … (see Saunders et al., 2005)
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References
-1
0
5
10
15
Deviation from eStat (500-8000 Hz)
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5332
0
4902
4472
-0.1
4042
3612
2322
-0.4
1032
602
200
-0.5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
0.9
7052
6622
0.8
6192
5762
-0.3
1462
1
7482
2752
SSQ-B question #
Accordingly, this poster focuses on the SSQ-B.
7912
-0.2
3182
1892
Data analysis is still ongoing for these two questionnaires, but so far, no
statistically significant relationship with hearing-aid gains has been found.
Looking at correlations between SSQ-B responses and
deviations from gain targets for each frequency suggests
that deviations in a high frequency range (4-6 kHz) drive
the correlation between mean SSQ-B scores and mean
deviations.
Cross-correlation
matrix for deviations
from gain targets
across frequencies
0.7
5332
4902
0.6
4472
0.5
4042
3612
0.4
3182
2752
0.3
2322
1892
0.2
1462
1032
0.1
602
200
200 602 1032 1462 1892 2322 2752 3182 3612 4042 4472 4902 5332 5762 6192 6622 7052 7482 7912
Frequency (Hz)
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Correlation coefficient*
Note: Two other outcome questionnaires were also tested in this study:
- Client Oriented Scale of Improvement (Dillon et al. 2007)
- International Outcome Inventory for Hearing Aids (Cox & Alexander, 2002)
Frequency (Hz)
5762
Correlation coefficient*
1 month
 Other questionnaires (SSQ-B, COSI, IOI-HA)
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2. Which frequencies drive the correlation?
7482
Final visit
r = -0.38
p = 0.0016
r2 = 0.1409
(Correlation remains after the three data points with
absolute deviations from targets larger than 10 dB are
removed: r = -0.34, p = 0.0056, r2 = 0.12)
mean (Gaussian-process regression)
95% confidence interval
Speech
1 month
...
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0
10
7912
 Adjust gains based on participant’s comments
Speech
intelligibility
Expectations
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SSQ-B scores are correlated with absolute
deviations from eStat targets , but %age of
variance explained (r2) is small (<15%).
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Gatehouse & Noble (2005); Jensen et al. (2009)
2nd fitting
Perceived
benefit
Analyses of large databases of real-ear + subjective measures offer a promising
avenue for further exploration of relationships between gains and benefit.
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Mean SSQ-B scores (across all questions) tend
to be highest when gains are close to eStat
targets (across 0.5—8 kHz).
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0.125
Cognitive factors
- Correlations were found primarily at high frequencies (4-6 kHz)
1. SSQ-B scores vs. mean deviations from eStat targets for the highest stimulus level
Speech, Spatial and Qualities B (SSQB) questionnaire
 SSQ questionnaire
 Fit to NAL-NL1 targets (real-ear measures)
 Adjust gains based on participant’s comments
… with a few exceptions (primarily, at low
frequencies).
SSQ-B scores co-vary with deviations from eStat gain targets
Questionnaires
1st fitting
… and unrelated to the amount of
hearing loss...
Gains
Loudness
‘Comfort’
Reasons for this outcome have yet to be identified.
120
0.125
Question #
Mean SSQ-B score
60
-5
Frequency (Hz)
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1 2 3 4 5 6 7 8 9 1011121314 1 2 3 4 5 6 7 8 9 1011121314151617 1 2 3 4 5 6 7 8 9 101112131415161718
Mean SSQ-B score
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-4
Left ear
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Hearing threshold (dB HL)
Hearing threshold (dB HL)
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This finding can be understood by considering that:
- hearing-aid gains are only one factor of perceived hearing-aid benefit (see, e.g., Saunders et al.,
2005; Jerram & Purdy, 2001)
- they influence perceived benefit indirectly, via loudness, speech intelligibility;
Correlation matrix
audiogram x SSQ-B responses
Mean SSQ-B responses versus
mean hearing loss
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Right ear
- The % of variance explained was small (<15 %)
Perceived hearing-aid benefit (SSQ-B) is not related to hearing loss
In particular, we were interested in how much of the variance in self-reports
of perceived benefit in hearing-aid users can be explained by deviations from
gain targets.
Methods
- Deviations from gain targets varied widely across participants
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In this study, we examine relationships between hearing-aid gains assessed
using real-ear measures and hearing-aid outcomes.
This is consistent with earlier findings (e.g., Boymans & Dreschler, 2012; Keidser et al., 2012).
NAL target
NAL REIG
Adjusted REIG, 1st visit
Adjusted REIG, 2nd visit (+/-SD)
eStat target
Soft (50 dB SPL)
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Substantial efforts have been devoted to the development of satisfactory
gain-prescription formulas (e.g., Dillon et al., 1998).
University of Salamanca, Salamanca, Spain Soniotica SL, Albacete, Spain
Discussion
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Background/Motivation
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Results
REIG (dB)
Overview
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Boymans M, Dreschler WA (2012) Audiologists-driven versus patient-driven fine tuning of hearing instruments. Trends Amplif 16, 4958
Cox RM, Alexander GC (2002) The International Outcome Inventory for Hearing Aids (IOI-HA): psychometric properties of the English
version. Int J Audiol 41, 30–35
Dillon H, James, A, Ginis J (1997). Client oriented scale of improvement (COSI) and its relationship to several other measures of benefit and satisfaction provided by hearing aids. J. Am. Acad. Audiol., 8, 27-43
Dillon H, Katsch R, Byrne D, Ching T, Keidser G, & Brewer S. (1998) The NAL-NL1prescription procedure for non-linear hearing aids.
National Acoustics Laboratories Research and Development, Annual Report 1997/98 (pp. 4-7). Sydney.
Gatehouse, S, Noble, W (2004) "The Speech, Spatial and Qualities of Hearing Scale (SSQ). Int. J. Audiol. 43, 85-9.
Jensen NS, Akeroyd MA, Noble W, Naylor G (2009) The Speech, Spatial and Qualities of Hearing scale (SSQ) as a benefit measure.
NCRAR conference on The Ear-Brain System: Approaches to the Study and Treatment of Hearing Loss. Portland, OR.
Jerram JC, Purdy SC (2001) Technology, expectations, and adjustment to hearing loss: predictors of hearing aid outcome. J. Am. Acad.
Audiol. 12(2), 64-79
Keidser G, Dillon H, Carter L, O'Brien A (2012) NAL-NL2 Empirical Adjustments. Trends Amplif 16, 211-223
Kochkin, S (2000) MarkeTrak V: Consumer satisfaction revisited. Hear J 53, 38–55
Kochkin, S (2005) Customer satisfaction with hearing instruments in the digital age. Hear J 58, 30–37
Rassmussen CE, Williams CKI (2006) Gaussian Processes for Machine Learning. MIT Press, Cambridge, MA.
Saunders GH, Chisolm TH, Abrams HB (2005) Measuring hearing aid outcomes--not as easy as it seems. J Rehabil Res Dev 42(4 Suppl
2), 157-168