2008-11-20 / News

Kids should turn down those iPods or risk hearing loss

By Eileen M. Daly

Years ago, legions of parents told their children to, "turn that stereo down or you'll go deaf." It turns out they were right. According to the National Institute of Health, harmful noise—sounds that are too loud or loud sounds that last a long time cause sensitive structures in the ear to become damaged. These structures, called hair cells, do not grow back once they are damaged and permanent noise-induced hearing loss may result.

Sound is measured in decibels. For example, normal conversation is measured at approximately 60 decibels, whereas discharging a small firearm produces a noise level of approximately 120 to 150 decibels. According to the National Institute for Occupational Safety and Health, the maximum safe exposure time to noise at 85 decibels is eight hours, while the maximum safe exposure time to noise at 110 decibels is one minute and 29 seconds.

With the advent of MP3 players and iPods, researchers are reporting increased exposure to dangerous levels of noise. According to Science Daily, audiologists began warning consumers about dangerous exposure to noise from walkmans and CD players back in the 1980s. MP3 players and iPods have a longer battery life, along with a capacity to hold more music, that often results in longer listening times.

The use of ear buds, listening devices that are placed directly into the ear canal, can cause the damage to be even greater. Dean Garstecki, a Northwestern University audiologist and professor, said, "We're seeing the kind of hearing loss in younger people typically found in aging adults. Unfortunately, the ear buds preferred by music listeners are even more likely to cause hearing loss than the muff-type earphones that were associated with the older devices." Garstecki and other specialists recommend using MP3 players and iPods for no more that an hour per day and at levels below 60% of the maximum volume.

A number of European countries have already enacted laws that place a volume limit of 100 decibels on iPods and MP3 players, but this is still well above safe listening levels. Moreover, as researchers have pointed out, volume is only one half of the equation. The amount of time spent listening to the devices also has an impact on the degree of hearing loss incurred. Brian Fligor of Children's Hospital in Boston said, "Studies have shown that people exposed to 85 decibels for eight hours tend to develop hearing loss. Every time you increase a sound level by three decibels, listening for half as long will produce the same amount of hearing loss."

Unfortunately, children are not listening to warnings about hearing loss any more now than they were back when parents were hollering about stereo use. The fact is, kids like loud music and seldom see hearing loss as a real danger. A recent study in Pediatrics reported that of the nearly 10,000 people who responded to an MTV website survey, only eight percent considered hearing loss "a very big problem."

One reason that kids may not consider hearing loss a real danger involves the fact that hearing loss generally occurs gradually rather than dramatically. If kids suddenly couldn't hear at all after blasting their iPods for a few hours, they might be more likely to listen to warnings. Instead, early symptoms of hearing loss occur very gradually. A recent scientific study from a team of nine specialists on the Scientific Committee on Emerging and Newly Identified Health Risks found that, "Regularly listening to personal music players at highvolume settings when young often has no immediate effect on hearing but is likely to result in hearing loss later in life."

Researcher William Martin Ph.D. of the Oregon Health and Science University Tinnitus Clinic reports, "Our own research shows that 16 percent of 6 to 19-year-olds have early signs of hearing loss at the range most readily damaged by loud sounds." Martin's advice? "Turn it down, walk away or protect your ears."

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