LOS ANGELES—By now, most Americans, teenagers included, have probably heard that exposure to loud music can be hazardous to their hearing. Yet a study by the House Clinic provides specific and alarming information about just how hazardous attending a rock concert can be.
In a presentation last month to the 2012 Meeting of the American Otologic Society, M. Jennifer Derebery, MD, lead author of the study, and colleagues from the House Clinic reported that 71% of teenagers said they experienced reduced hearing or tinnitus (ringing in the ears) immediately after attending a rock concert last summer at the Staples Center in Los Angeles.
The clinic gave the young people free tickets to the concert, after getting parental consent. The teenagers were told of the importance of hearing protection and advised to use the foam earplugs provided to them. However, only three of the 29 chose to do so.
During the concert, three adult researchers accompanied the teenagers, who were seated approximately 15 to 18 rows up from the floor of the auditorium. Using a calibrated sound pressure meter, the researchers took 1645 measurements of sound decibel (dBA) levels during the three-hour concert. The sound levels ranged from 82 to 110 dBA, with an average of 98.5 dBA. The mean level was above 100 dBA for 10 of the 26 songs.
The House Clinic team tested the teens’ hearing both before and after the concert.
While all those chosen to participate in the study had been found to have normal hearing, after the concert 54% of them thought that they were not hearing as well as they had been before the concert. Twenty-five percent said they had tinnitus.
The researchers also conducted distortion product otoacoustic emissions (DPOAE) tests on all the teenagers. This test measures the function of the outer hair cells in the inner ear, which are believed to be the most vulnerable to damage from prolonged exposure to noise. The results showed that more than half the subjects had significantly reduced outer hair cell function.
A TEMPORARY LOSS—PROBABLY
In most cases, hearing loss observed after a rock concert or comparable noise exposure reflects a temporary shift of hearing thresholds, not a permanent hearing loss. It usually disappears within a day or two of the event.
However, that is not always the case. A single exposure to excessive sound, or the fifth or tenth in a series of exposures can in some cases result in hearing loss or tinnitus that does not go away.
Derebery, who is the lead author of an article on the House study that will be published in Otology & Neurotology, warned, “Teenagers need to understand a single exposure to loud noise either from a concert or personal listening device can lead to hearing loss. With multiple exposures to noise over 85 decibels, the tiny hair cells may stop functioning and the hearing loss may be permanent.”
The study was funded through the House Research Institute’s national teen hearing loss prevention initiative, It’s How You Listen that Counts®, as part of its Sound Partners hearing conservation education program. The institute offers online information for teenagers on preventing hearing loss.