[Risk of hearing loss caused by listening to music with head phones]

Sound levels of music played from mini-cassette players via headphones were measured in a nonrepresentative group of 681 pupils whose ages were between 10 to 19 years. Each pupil completed a questionnaire giving the total time spent listening to music each day. The pupils set the music levels (free field corrected short time Leq) between 60 dB(A) and 110 dB(A). In the age group from 12-16 years, 10% chose 110 dB(A). Nearly 50% of the total group usually listened to music less than one hour per day, and just less than 10% listened for four or more hours. The energy equivalent of continuous sound pressure level for an exposure time of 8 h per day was for 55% Leq 8 h < 66 dB(A) and for 7% Leq 8 h > 95 dB(A) while 4% had an Leq 8 h > 105 dB(A). Estimation of the expected hearing losses (HL) were based on ISO 1999: about 10% of the total group were predicted to have a HL > 10 dB at 4 kHz after 5 years. After listening to sound in this manner 0.3% were expected to develop hearing losses at age 25 years that would be severe enough to substantially impair speech intelligibility.