University of Missouri - Columbia.
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Posted 10.04.05

Hearing Researchers Warn of 'Direct Delivery' Danger

Loud Sound Levels Not Good for the Ears

COLUMBIA, MO -- Plugging into the latest music may mean you are setting yourself up to tune it out in the future. The popularity of personal listening devices, such as MP3 players, is not welcome news to experts such as Barbara McLay, who oversees a hearing conservation program at the University of Missouri-Columbia.

"Direct delivery of music into ears can cause hearing loss over time," said McLay, clinical associate professor in MU's School of Health Professions. "All of the noise we are exposed to adds up over time and wears on our hearing."

Noise-induced hearing loss is irreversible. According to McLay, the closer people are to the source of a sound the more damage it can do to their hearing. She says if other people can hear the music when people are wearing headphones or ear buds, then it is too loud. It's also important to give the ears a break; listening to music the majority of the day, even at moderate levels, can still have a significant damaging effect.

"Most people are aware that concert-level music is a dangerously high level of sound. If you look closely, you will actually see that most musicians are wearing protective ear plugs to safeguard their hearing," McLay said.

McLay said it is easy to tell if someone has been exposed to levels of sound that are too loud. Following the exposure to loud noise, hearing may be temporarily impaired. While normal hearing will return, there has still been an irreversible loss of cells. If people have to raise their voice to be heard, the environment is too loud. Another sign of overexposure to loud noise is experiencing ringing in the ears, known as tinnitus.

"Noise-induced hearing loss sneaks up on people. Someone can have hearing loss and not realize it because it starts in the higher frequencies," McLay said. "Typically, the hearing loss is gradual and over time it begins to sound like people are mumbling. There is no treatment; once you have this type of hearing loss, it is permanent and all you can do is keep it from getting worse."

McLay oversees a hearing conservation program on the University of Missouri-Columbia campus. An educational program about noise-induced hearing loss is presented to employees in the power plant, landscape services, maintanence and construction. The workers also have annual hearing tests.

"It has taken many years for this to come to the forefront of thinking because nobody thinks it will happen to them," McLay said. "I have seen a shift in attitude because of the greater awareness that our educational program brings."



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