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M. Jennifer Derebery, MD, House Clinic physician, along with theHouse Research Institute tested teens" hearing before andafter a concert and presented the study findings at the AmericanOtologic Society meeting on April 21, 2012. The study has beenaccepted for publication in an upcoming issue of Otology & Neurotology . The hearing loss that may be experienced after a pop rock concertis not generally believed to be permanent. It is called a temporarythreshold shift and usually disappears within 16-48 hours, afterwhich a person"s hearing returns to previous levels. "Teenagers need to understand a single exposure to loud noiseeither from a concert or personal listening device can lead tohearing loss," said M. Jennifer Derebery, MD, lead author andphysician at the House Clinic. "With multiple exposures tonoise over 85 decibels, the tiny hair cells may stop functioningand the hearing loss may be permanent." In the study, twenty-nine teenagers were given free tickets to arock concert. To ensure a similar level of noise exposure for theteens, there were two blocks of seats within close range of eachother. The seats were located in front of the stage at the far endof the venue approximately 15-18 rows up from the floor. Parental consent was obtained for all of the underage studyparticipants. The importance of using hearing protection wasexplained to the teenagers. Researchers then offered hearingprotection to the subjects and encouraged them to use the foam earplugs. However, only three teenagers chose to do so. Three adult researchers sat with the teenagers. Using a calibratedsound pressure meter, 1,645 measurements of sound decibel (dBA)levels were recorded during the 26 songs played during the threehour concert. The sound levels ranged from 82-110 dBA, with anaverage of 98.5 dBA. The mean level was greater than 100 dBA for 10of the 26 songs. The decibel levels experienced at the concert exceeded what isallowable in the workplace, according to Occupational Safety andHealth Administration (OSHA). OSHA safe listening guidelines settime limits for exposures to sound levels of 85 dB and greater inthe workplace. The volumes recorded during the concert would haveviolated OSHA standards in less than 30 minutes. In fact, one thirdof the teen listeners showed a temporary threshold shift that wouldnot be acceptable in adult workplace environments. Following the concert, the majority of the study participants alsowere found to have a significant reduction in the DistortionProduct Otoacoustic Emissions (OAE) test. This test checks thefunction of the tiny outer hair cells in the inner ear that arebelieved to be the most vulnerable to damage from prolonged noiseexposure, and are crucial to normal hearing, the ability to hearsoft (or low level sounds), and the ability to understand speech,especially in noisy environments. With exposure to loud noise, theouter hair cells show a reduction in their ability to function,which may later recover. However, it is known that with repeatedexposure to loud noise, the tiny hair cells may become permanentlydamaged. Recent animal research suggests that a single exposure toloud noise may result in permanent damage to the hearing nerveconnections themselves that are necessary to hear sound. Following the concert, 53.6 percent of the teens said they did notthink they were hearing as well after the concert. Twenty-fivepercent reported they were experiencing tinnitus or ringing intheir ears, which they did not have before the concert. Researchers are especially concerned, because in the most recentgovernment survey on health in the United States National Healthand Nutrition Examination Survey (NHANES) 2005-2006, 20% ofadolescents were found to have at least slight hearing loss, a 31%increase from a similar survey done from 1988-1994. The findings of the study clearly indicate more research isnecessary to determine if the guidelines for noise exposure need tobe revised for teenagers. More research is also needed to determineif teenager"s ears are more sensitive to noise than adults. "It also means we definitely need to be doing more to ensurethe sound levels at concerts are not so loud as to cause hearingloss and neurological damage in teenagers, as well asadults," said Derebery. "Only 3 of our 29 teens choseto use ear protection, even when it was given to them and they wereencouraged to do so. We have to assume this is typical behavior formost teen listeners, so we have the responsibility to get the soundlevels down to safer levels." Researchers recommend teenagers and young adults take an activerole in protecting their hearing by utilizing a variety of soundmeter ‘apps" available for smart phones. The soundmeters will give a rough estimate of the noise level allowingsomeone to take the necessary steps to protect their hearing suchas wearing ear plugs at a concert. In addition, Derebery and the study co-authors would like to seeconcert promoters and the musicians themselves take steps to lowersound levels as well as encourage young concert goers to usehearing protection. The study was funded through the House Research Institute"snational teen hearing loss prevention initiative, It"s HowYou Listen that Counts®, as part of its broader Sound Partnershearing conservation education program. The e-commerce company in China offers quality products such as Retractable Banner Stand Manufacturer , China Bus Stop Shelter Advertising, and more. For more , please visit Large Format Poster Printing today!
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