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Whether your taste is heavy metal or pop, if you're headed to a concert, don't forget to take your earplugs. If you don't, you risk damaging your hearing and eventually suffering noise-induced hearing loss.
That's the conclusion of a new study to be presented at the American Academy of Otolaryngology/Head and Neck Surgery's annual meeting, which will begin on Sept. 25 in Los Angeles.
The advice also holds whether you're in a front-row seat or in the "nosebleed" section, says lead investigator Dr. David A.
Opperman, chief resident at the University of Minnesota's department of otolaryngology in Minneapolis.
"No seat is a good one without earplugs," he says.
Opperman and his colleagues assigned 29 men and women, ranging in age from 17 to 59, to sit in a variety of seats while attending concerts featuring heavy metal, pop or rockabilly music. Two people were placed in each location, whether front row, stage left, stage right or far from the stage. One person in each location wore earplugs, while the other did not.
Before the concerts the study participants all had normal or near-normal hearing "thresholds," based on the results of a hearing test called an audiogram. A threshold is the softest sound you can hear on an audiogram.
When audiograms were given again after the concerts, the researchers found, 64 percent of those not wearing earplugs had significant hearing-threshold shift, in which they couldn't hear a sound as soft as they could before the concert, compared to only 27 percent of those wearing earplugs.
"A threshold shift is a decrease in the ability to hear as represented on an audiogram," Opperman says. "The ability to hear before the show was better than the ability afterward."
The shifts occurred regardless of seat location or type of music.
"The genre of music doesn't seem to matter," Opperman says.
"The misconception that heavy metal is worse than pop puts the people at the pop concert at more risk."
When the researchers measured sound levels at the concerts, they found that the maximum was 125 decibels. Prolonged exposure to noises of about 85 decibels can damage hearing, according to the academy.
It is not only the loudness of music at concerts that puts hearing at risk, but also crowd noise, which also can be quite loud.
"We observed the ambient noise from the crowd was more than ambient," Opperman says. "It was significant."
Other studies have found that noise levels from crowds at sporting events can reach 125 decibels, Opperman adds, nearly the noise level heard during auto races.
It's not known whether the hearing loss experienced by the study participants was permanent, he says, because the researchers didn't perform follow-up exams after the post-concert test.
"That was partly due to the difficulty of getting them to come back in three months for audiograms," Opperman says.
"They may not have any permanent loss from that concert," Opperman says, but he adds that accumulated damage can result in hearing loss.
Sigfrid Soli, a scientist at the House Ear Institute in Los Angeles, says that the study is the first of this type that he has seen, but the results are no surprise.
"The results are entirely predictable and expected," Soli says. "If you have excessive exposure to noise, your inner ear gets tired and needs some time to recover. During this period of tiredness and recovery, depending on the extent of the noise exposure, you have a temporary increase in your hearing threshold."
Whether that will result in permanent hearing damage depends on how often you are exposed to sound, how long and at what volume, Soli says. Experts debate the issue, but research for the workplace has found that people exposed to sound levels of 85 decibels for an eight-hour workday for 40 years of working life are at risk of hearing loss of 7.9 percent by age 60.
"But if you go to 90," he says, "it goes up to 25 percent."
Opperman says that his study proves that earplugs work, though they are not perfect, as shown by the finding that even some of those wearing the devices had threshold shifts.
"The earplugs may not have fit properly," he speculates.
"Persons may not use them properly."
Many performers now wear earplugs, Opperman says, aware that prolonged exposure can damage their hearing. But getting concertgoers to use them can be a tough sell.
"People don't want to wear them," he says. "Two people in the study randomized to wear earplugs refused and had to drop out of the study."
Opperman suggests that in buying earplugs, which are available over the counter, people should choose ones that reduce noise by 21 decibels. Another option is custom-made earplugs, available from an audiologist, which can fit better and provide better protection than over-the-counter models.
c.2005 HealthDay News