the use of mp3 players as a possible cause of nihl

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


Audiology

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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


Audiology

1. Website Oorcheck.nl

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Oorcheck.nl


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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

Oorcheck.nl


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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


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


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


Audiology

Average output levelsof 103 fragments, classified in 9 musical styles

mp3check.nl


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)

mp3check.nl


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3. Results from 100.000 users

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Results mp3check.nl


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


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


Audiology

The effects of musical style

Differences in exposure levels for different musical

styles

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Results mp3check.nl


Audiology

4. A model for the sensitivity to MIHL

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Risk assessment


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


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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5 Conclusions

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Conclusions


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


Audiology

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Thanks for your

attention

Questions?


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

the use of mp3 players as a possible cause of nihl

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