May 25, 2012 12:00 PM by Mary Elizabeth Dallas
FRIDAY, May 25 (HealthDay News) -- Exposure to loud music at a rock concert often results in temporary hearing loss for teenagers, researchers say.
A small study by the House Research Institute revealed that 72 percent of teens reported reduced hearing after attending a three-hour show. This type of hearing loss typically disappears within 48 hours, but if it occurs repeatedly, permanent hearing loss can develop, the study authors noted.
"Teenagers need to understand a single exposure to loud noise either from a concert or personal listening device can lead to hearing loss," study lead author Dr. M. Jennifer Derebery, physician at the House Clinic, said in an institute news release. "With multiple exposures to noise over 85 decibels, the tiny hair cells may stop functioning and the hearing loss may be permanent."
For the study, researchers offered 29 teenagers free tickets to a rock concert. All of the seats were about 15 to 18 rows away from the stage.
Beforehand, the kids were told how they could protect their hearing and were encouraged to use foam ear plugs during the performance. Only three chose to use them, the study authors noted.
Using a calibrated sound pressure meter, researchers seated with the teens found that sound decibel levels (dBA) ranged from 82 to 110 dBA and averaged 98.5 dBA. The average was greater than 100 dBA for 10 of the 26 songs played.
Derebery and colleagues noted that these levels exceeded the workplace safety standards of the U.S. Occupational Safety and Health Administration, which sets time limits on exposure to sound levels of 85 dB or greater.
Following the concert, most of the teens had a significant reduction in the Distortion Product Otoacoustic Emissions test, which checks the function of cells in the inner ear. These cells are critical to normal hearing and most vulnerable to damage from prolonged noise exposure.
Specifically, 53.6 percent of the teens said they were not hearing as well as they did before the concert, and 25 percent reported tinnitus, which is ringing in the ears.
Although these cells usually recover, the researchers cautioned that repeated exposure to loud noise could permanently damage hearing.
The authors said more research is needed to determine if teenage ears are more sensitive than adult ears. Guidelines for noise exposure among teenagers may need to be updated, they added.
"It also means we definitely need to be doing more to ensure the sound levels at concerts are not so loud as to cause hearing loss and neurological damage in teenagers, as well as adults," said Derebery. "Only three of our 29 teens chose to use ear protection, even when it was given to them and they were encouraged to do so. We have to assume this is typical behavior for most teen listeners, so we have the responsibility to get the sound levels down to safer levels."
The researchers pointed out that teenagers should take advantage of sound meter "apps" available for smartphones, which provide an estimate of surrounding noise level, and use ear protection when appropriate.
The study, recently presented at an American Otologic Society meeting, will be published in a future issue of Otology & Neurotology.
The U.S. National Institute on Deafness and Other Communication Disorders has more about noise-induced hearing loss.