1. linical & Experimental Audiology The use of mp3 players as a possible cause of NIHL Wouter Dreschler (w.a.dreschler@amc.nl)w.a.dreschler@amc.nl Academic Medical Centre, Amsterdam, The Netherlands Jan de Laat Leiden University Medical Centre, Leiden, The Netherlands

2. 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)www.mp3check.nl 3.Results in 100.000 users 4.A model for the sensitivity to MIHL 5.Conclusions Contents

3. linical & Experimental Audiology 1. Website Oorcheck.nl 3 27-2-2010 Oorcheck.nl

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6. linical & Experimental Audiology 6 27-2-2010 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 Oorcheck.nl

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8. linical & Experimental Audiology Results as a function of age Oorcheck.nl

9. linical & Experimental Audiology Subjective versus objective results Oorcheck.nl

10. linical & Experimental Audiology 2. Website mp3check.nl 10 27-2-2010

11. linical & Experimental 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

12. linical & Experimental Audiology Average output levels of 103 fragments, classified in 9 musical styles mp3check.nl

13. linical & Experimental Audiology Max.output per musical style and mp3 player mp3check.nl

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21. linical & Experimental Audiology 3. Results from 100.000 users 21 27-2-2010 Results mp3check.nl

22. linical & Experimental Audiology Characteristics of mp3-use (n=100.000) 22 27-2-2010  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

23. 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 23 27-2-2010 Results mp3check.nl

24. linical & Experimental Audiology The effects of musical style Differences in exposure levels for different musical styles 24 27-2-2010 Results mp3check.nl

25. linical & Experimental Audiology 4. A model for the sensitivity to MIHL 25 27-2-2010 Risk assessment

26. 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 HTL 234  < 5 dB: safe (green)  5-10 dB: marginal (orange)  > 10 dB: unsafe (red)  Predictions based on ISO-1999 (P50) Risk assessment

27. linical & Experimental Audiology Not just the output level !! large change moderate change Very small change Change for permanent NIHL Risk assessment

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31. linical & Experimental Audiology 5 Conclusions 31 27-2-2010 Conclusions

32. 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

33. linical & Experimental Audiology 33 Thanks for your attention Questions?

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35. linical & Experimental Audiology Results as a function of age Oorcheck.nl