WEDNESDAY, June 23 (HealthDay News) -- Temporary changes in hearing sensitivity associated with MP3 players suggest that the devices could have potentially harmful effects, according to research published in the June issue of the Archives of Otolaryngology -- Head & Neck Surgery.
Hannah Keppler, of Ghent University in Belgium, and colleagues analyzed A-weighted sound pressure levels on a head and torso simulator from an hour of pop-rock music on an MP3 player. Also, 21 young adults listened to six hour-long sessions of pop-rock music using two types of headphones with an MP3 player at multiple preset gain settings. A control group was also used.
The researchers found that the output levels at the full gain setting were 97.36 dBA for supra-aural headphones and 102.56 dBA for stock earbuds. The noise-exposure group had significant changes in hearing thresholds and transient-evoked otoacoustic emission amplitudes measured before and after exposure. Significant differences in the rate of threshold or emission shifts were noted between nearly every session of the noise-exposure group compared to the control group.
"The development of a permanent threshold shift cannot be predicted from the initial temporary threshold shift, but, considering the reduction in hearing sensitivity after listening to a personal music player, these devices are potentially harmful," the authors conclude.
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