Title: The use of mp3 players as a possible cause of NIHL
1The use of mp3 players as a possible cause of
NIHL
- Wouter Dreschler (w.a.dreschler_at_amc.nl)
- Academic Medical Centre, Amsterdam, The
Netherlands - Jan de Laat
- Leiden University Medical Centre, Leiden, The
Netherlands
2Contents
- Screening tests at the internet (www.oorcheck.nl)
- Check of mp3-exposure at the internet
(www.mp3check.nl) - Results in 100.000 users
- A model for the sensitivity to MIHL
- Conclusions
Contents
31. Website Oorcheck.nl
Oorcheck.nl
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6Online 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
Oorcheck.nl
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8Results as a function of age
Oorcheck.nl
9Subjective versus objective results
Oorcheck.nl
102. Website mp3check.nl
11Technical measurents on HATS manikin
- Tested
- gt30 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
12Average output levelsof 103 fragments,
classified in 9 musical styles
mp3check.nl
13Max.output per musical style and mp3 player
mp3check.nl
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213. Results from 100.000 users
Results mp3check.nl
22Characteristics of mp3-use (n100.000)
- 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
23Levels of sound exposure (n100.000)
- The output levels are gt 90 dB(A) for 21 if the
subjects - However, these levels may be corrected for
exposure duration - Safe exposure 76 of the users
- lt80 dBA _at_ 40 h/w, lt83 dBA _at_ 20 h/w, lt86 dBA _at_ 10
h/w, etc. - Higher exposure 24 of the users
Results mp3check.nl
24The effects of musical style
-
- Differences in exposure levels for different
musical styles
Results mp3check.nl
254. A model for the sensitivity to MIHL
27-2-2010
25
Risk assessment
26Hypotheses in risk assessment
- MIHL NIHL
- Levels gt 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
- lt 5 dB safe (green)
- 5-10 dB marginal (orange)
- gt 10 dB unsafe (red)
- Predictions based on ISO-1999 (P50)
Risk assessment
27Not just the output level !!
Risk assessment
2827-2-2010
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315 Conclusions
27-2-2010
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Conclusions
32Conclusions
- 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
33Thanks for your attention
Questions?
33
34Thanks for your attention
35Results as a function of age
Oorcheck.nl