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Just one hour's listening to an MP3 player can damage hearing,claim scientists.It causes temporary changes in hearing sensitivity which may lead to long-term harm,according to a new study.
The findings show over -stimulation of hair cells within the ear occurs even at varying volume levels for short periods of time.The study of almost 60 young people carried out by researchers at Ghent University,Belgium,is published in the Archives of Otolaryngology -Head&Neck Surgery journal.
It follows previous warnings from doctors that using MP3 players at high volumes with earphones that fit into the ear canal could lead to loss of hearing. In the latest study,21 people aged 19 to 28 years were exposed to pop and rock music using MP3 players at varying volumes for one hour. A second group of 28 men and women were a control group who were not exposed to MP3 music.
Hearing tests were carried out before and after the exposure,which found significant threshold or emission shifts were observed between almost every session of the noise exposure group compared with the control group.Lead researcher Hannah Kempler said:Excessive noise exposure can lead to metabolic and mechanical effects resulting in alterations of the structural elements of the inner ear that contains auditory sensory cells or"hair cells".
The European Commission has warned up to 10% of 30-year-old would have to wear a hearing device within the next decade because they listen to music too loudly through headphones.Surveys showed more than 90% of young people in Europe and the U.S.used MP3 players,often for several hours a day at maximum volume.Hearing experts recommend the 60/60 rule一listening to MP3 players for no more than 60 minutes at a time at 60% of maximum volume.Concern among EU health and safety officials has led to plan to ensure all MP3 players have the same maximum volume of 85 decibels(dB)一although users may be able to individually override it at their own risk.

Not much difference was found between the exposure group and the control group according to the hearing tests after the exposure.
A:Right
B:Wrong
C:Not mentioned