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linical & Experimental
Audiology
The use of mp3 players as a possible cause of NIHL
Wouter Dreschler ([email protected])
Academic Medical Centre, Amsterdam, The Netherlands
Jan de Laat
Leiden University Medical Centre, Leiden, The Netherlands
linical & Experimental
Audiology
2
27-2-2010
Contents
1. Screening tests at the internet (www.oorcheck.nl)
2. Check of mp3-exposure at the internet (www.mp3check.nl)
3. Results in 100.000 users
4. A model for the sensitivity to MIHL
5. Conclusions
Contents
linical & Experimental
Audiology
1. Website Oorcheck.nl
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Oorcheck.nl
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Audiology
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Audiology
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Audiology
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Online speech-in-noise tests
Speech-in-noise tests
Spectrum of masking noise is
equal to speech spectrum
Adjustable presentation level
Adaptive procedure
2 dB steps up-down
Fixed noise level
SRT: 50% correct recognition
Average signal-to-noise ratio
over stimuli
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Audiology
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Audiology
Results as a function of age
Percentual distribution of outcome classesas a function of age
0%
20%
40%
60%
80%
100%
25 t/m 35 36 t/m 45 46 t/m 55 56 t/m 65 66 t/m 98Age decade
Poor
Insufficient
Good
Oorcheck.nl
linical & Experimental
Audiology
Subjective versus objective results
Percentual distribtion of the differences between subjective and objective results
0%
20%
40%
60%
80%
100%
12 t/m 15 16 t/m 18 19 t/m 24Age category
poorer than thought
about equal
better than thought
Oorcheck.nl
linical & Experimental
Audiology
2. Website mp3check.nl
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Audiology
Technical measurents on HATS manikin
Tested:• >30 mp3-spelers• different earphones• four positions of the
volume wheel• different musical styles
Effects:• coding strategy almost absent• Musical style moderately strong• Mp3-player: large!• Earphone: very large !!
mp3check.nl
linical & Experimental
Audiology
Average output levelsof 103 fragments, classified in 9 musical styles
mp3check.nl
linical & Experimental
Audiology
Max.output per musical style and mp3 player
no
rmru
is
elec
folk
hip
ho
p
jazz
klas
siek
lati
n
po
p
r&b
rock
iPod Nano 96 94,6 93,7 95,3 93,7 88,6 94,5 93,6 89,4 92,7
Creative Muvo 102,4 100,6 100,3 101,6 100,5 95,4 101,2 100,2 96,1 99,2
Creative Zen 102,5 100,9 100,2 101,7 100,4 95,3 101,2 100,2 96,2 99,2
Sweex Bluebay 113,3 111,4 111,5 112,4 111,9 106,4 112,4 111,3 107,1 110,2
iPod Shuffle 102,2 100,5 99,8 101,5 99,7 94,9 100,6 99,7 95,7 98,8 Packard Bell Pulse 99,7 98 97,3 98,8 98,2 92,3 98,8 97,7 93,2 96,6
Philips SA3125 97,1 95,7 99,1 96,5 94,7 89,8 95,6 94,7 90,6 93,8
Samsung K3 106,5 104,5 104,3 105,7 104,2 99,6 105,1 104 100,4 103,1
Sandisk Sansa 95,4 93,7 93,3 94,6 93,9 88,2 94,5 93,4 88,9 92,3
Sony A1200 97,8 96 95,8 96,9 96,2 90,8 96,8 95,7 91,5 94,6
intensiteit per muzieksoort bij maximaal volume in dB(A)
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3. Results from 100.000 users
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Results mp3check.nl
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Audiology
Characteristics of mp3-use (n=100.000)
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22% of the users uses the upper 20% of the volume range
76% of the users listens less than 10 hours per week
Results mp3check.nl
linical & Experimental
Audiology
Levels of sound exposure (n=100.000)
The output levels are > 90 dB(A) for 21% if the subjects
However, these levels may be corrected for exposure duration
• “Safe” exposure: 76% of the users[<80 dBA @ 40 h/w, <83 dBA @ 20 h/w, <86 dBA @ 10 h/w, etc.]
• “Higher exposure: 24% of the users
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Results mp3check.nl
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Audiology
The effects of musical style
Differences in exposure levels for different musical
styles
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Results mp3check.nl
linical & Experimental
Audiology
4. A model for the sensitivity to MIHL
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Risk assessment
linical & Experimental
Audiology
Hypotheses in risk assessment
MIHL = NIHL• Levels > 75 dBA may contribute to damage
• Exchange rate: 3 dB
• Exposure calculated re. 40 hours/week
Adapted risk model• MIHL after 10 years of use
• Focus on HTL234
< 5 dB: safe (green) 5-10 dB: marginal (orange) > 10 dB: unsafe (red)
Predictions based on ISO-1999 (P50)
Risk assessment
linical & Experimental
Audiology
Not just the output level !!
0
1
2
3
4
5
6
7
8
75 80 85 90 95 100 105 110 115
Gemiddeld geluidsniveau in dBA
blo
ots
telli
ng
sd
uu
r in
(u
ren
)kans op blijvende gehoorschade
large
change
moderate
change
Very small
change
Change for permanent NIHL
Risk assessment
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Audiology
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Audiology
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5 Conclusions
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Conclusions
linical & Experimental
Audiology
Conclusions
Unexpectedly, about 20-30% of young subjects have
deteriorated hearing for speech in noise
MIHL is a possible cause
Mp3 players form a non-neglible part of the sound
exposure in youngsters
Therefore, there is need for action
• Limitation of max. Output levels (as in the EU)?
• Counseling and awareness
• Large-scale screening with a test sensitive for MIHL
Conclusions
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Audiology
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Thanks for your
attention
Questions?
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Audiology
Thanks for your attention
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Audiology
Results as a function of age
Percentual distribution of outcome classesin younger subjects
0%
20%
40%
60%
80%
100%
12 t/m 15 16 t/m 18 19 t/m 24
Poor
Insufficient
Good
Oorcheck.nl