Loud rock music contributed to hearing loss among baby boomers, but MP3
players are poised to make the problem much worse for the next generation.
New surveys from the American Speech-Language-Hearing Association highlight
that risk, noting that high school students are much more likely than adults to
blast the volume in their MP3 players, raising the risk of hearing loss later
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These devices, which pump music through headphones directly into the ear
canal, enable the user to overcome the rumble of the subway or the drone of an
airplane engine without drawing angry shouts of "turn it down!"
As a result, they easily desensitize the user to dangerously high sound
levels. A CD player and a Walkman do too, but MP3 players such as the iPod pose
an additional danger.
Because they hold thousands of songs and can play for hours without
recharging, users tend to listen continuously for hours at a time. They don't
even have to stop to change a CD or a tape.
Longer Listening, More Damage
Since damage to hearing caused by high volume is determined by its duration,
continuous listening to an MP3 player, even at a seemingly reasonable level,
can damage the delicate hair cells in the inner ear that transmit sound
impulses to the brain.
Increasing reports like this have caused U.S. lawmakers to step in. Earlier
this year, Rep. Edward Markey (D-Mass.) asked the National Institutes of Health
to research the potentially devastating effects posed by earbud headphones. The
NIH recently responded by saying, "Any type of headphone has the potential
to cause [noise-induced hearing loss] if used improperly in terms of absolute
level of the sounds, the length of exposure time to sound, and the fit of the
earphone or headphone." They add that more research is still needed to
determine if a particular type of earphone increases the risk.
"Studies have shown that people exposed to 85 decibels for eight hours
tend to develop hearing loss," Brian Fligor, ScD, of Children's Hospital in
Boston, tells WebMD. He found that all the CD players he examined produced
sound levels well in excess of 85 decibels.
"Every time you increase a sound level by three decibels, listening for
half as long will produce the same amount of hearing loss. The kid who cuts my
grass uses an iPod. The lawn mower noise is about 80 to 85 decibels. If he
likes listening to his iPod 20 decibels above that, he's in the range of
100-105 decibels. At that sound level he shouldn't listen for more than eight
to 15 minutes."
But if he's like millions of other iPod owners, the boy probably listens for
several hours a day, placing a large noise burden on his hearing even if he
turns it down when he's not cutting grass.