Copyright 2006 Post-Newsweek Media, Inc.
All Rights Reserved
January 17, 2006, Tuesday
LENGTH: 1784 words
HEADLINE: The iPod and the Fury
BYLINE: Gregory Mott; Washington Post Staff Writer
DATELINE: United States
If recent reports are to be believed, those sleek iPod earbuds may carry risks beyond marking wearers as mugger-bait.
if to rain on Apple's holiday parade -- the company reported sales of
14 million iPods in the last quarter of 2005, bringing total sales for
the product to more than 42 million -- audiologists and other hearing
experts have been issuing warnings in recent weeks that improper use of
iPods and other personal stereo systems can dramatically heighten risk
of hearing loss, particularly in young people.
this just a case of advocacy groups seizing upon a teachable moment to
fly their banners -- or is there really a chance that being able to
hold your entire music library in your palm can come at the cost of
your hearing? Time for a reality check.
experts agree that hearing loss is increasing in the United States.
According to widely cited figures from the American
Speech-Language-Hearing Association (ASHA), the number of Americans age
3 and older with some form of auditory disorder has more than doubled
since 1971, from 13.2 million to about 30 million today. Of those,
one-third are said to be people with noise-induced hearing loss.
trend clearly predates the iPod; in fact, it traces its roots to the
dawn of the industrial age, according to Pam Mason, ASHA's director of
audiology professional practices. These new devices merely add to a
daily din of environmental noise that includes traffic, construction,
jets, nightclubs, leaf blowers and surround sound home theater systems.
certain percentage of people are going to experience hearing loss
because of genetic predisposition, and by age 65 about a third of the
population will experience some age-related hearing loss," or
presbycusis, said Brenda Lonsbury-Martin, ASHA's director of research
and science. "Old-age hearing is an accumulation of exposure to loud
noise over the years, exposure to ototoxic drugs [more than 130
medications, including some commonly used drugs, can cause or
contribute to hearing loss, according to ASHA], smoking and a number of
things that accumulate over time. Once this loss starts to occur, if
you continue to add noise insult, you're more at risk."
damage occurs when loud sound destroys tiny hair cells in the inner
ear. These cells are responsible for converting sound waves into
electrical impulses, which are then sent to the brain. Once 25 to 30
percent of these cells disappear, Lonsbury-Martin said, you begin to
experience hearing loss.
looking at users of personal cassette players and Walkman-type portable
compact disc players have found increased risk of hearing loss among
people who listen to loud music through headphones for extended periods
of time. And there are anecdotal reports of hearing damage complaints
associated with newer devices.
But essentially, iPods are too new, and noise-induced hearing loss too gradual, to be reflected in the latest statistics.
hearing loss is something that develops slowly and insidiously. . . .
Even in those people who are rather susceptible, it would be unexpected
for them to develop any significant hearing loss for a while, meaning
years and maybe a decade," said Brian J. Fligor, director of diagnostic
audiology at Children's Hospital in Boston.
recent warnings about hearing loss and personal music devices cite
Fligor's research on portable CD players. In the case of one brand of
player matched with a particular brand of earphone, he found that
listeners could get a sound dose as high as 120 decibels. This is
comparable to the sound level at a loud rock concert or sandblasting;
it could lead to risk of hearing damage after 7.5 minutes of exposure.
data on iPods and similar devices have found lower maximum levels --
above 100 decibels (the noise volume of a chainsaw; risk of hearing
damage after two hours), but not higher than 115 decibels (a football
game in a loud stadium; risk of hearing damage after 15 minutes),
Fligor said. To fully understand the potential impact of these devices,
it is important to know that the sound is traveling a tiny distance
from your earbud to your eardrum rather than being diffused in a
football stadium or concert arena.
declined to provide information on the maximum output level for its
devices, and noted that the federal government does not require
manufacturers to provide such information to consumers.
course, some criticism of these newer devices stems from the very
technological advances that have helped to make them so popular.
Digital technology has made it possible to play music in these devices
at loud volumes without the signal distortion produced by, say, a
transistor radio. And Apple touts its newest iPods as being capable of
holding up to 15,000 songs and being able to play for up to 20 hours on
a fully charged battery. Therein lies potential for trouble.
you use them at high volume for eight hours there's no doubt -- you
could have steel ears and you would still have some damage,"
Lonsbury-Martin said. "There's a point where even resistant ears will
But hearing damage isn't the
same thing as hearing loss, and the effects of temporary exposure to
loud sound don't have to be lasting "if you pay attention to your ear
health," said Lonsbury-Martin.
the advice to a personal stereo user who experiences muffled or dulled
hearing after listening would be the same as for any person coming out
of a loud environment: Don't go back into the loud environment, be it a
noisy club or a set of ear buds, until the symptoms pass. And consider
protecting yourself against similar exposure in the future.
findings with CD players led him to prescribe as a safe portable stereo
dosage one hour per day at 60 percent of maximum volume, a level that
would fall below the 85 decibel mark at which the Occupational Safety
and Health Administration (OSHA) says the risk of hearing damage
begins. Fligor notes that this is meant more as a guide to
self-regulation than a hard and fast rule.
tolerances and preferred listening levels vary, said Fligor, who uses
an iPod himself and sets his personal levels at two hours per day at
about 89 decibels, which would be slightly above his 60 percent
Even if iPod users were to
limit listening to an hour per day, experts agree, ambient noise -- on
the Metro, on city streets or even in an office setting -- could
challenge efforts to keep the volume down to 60 percent of maximum.
people try to use the iPod to try to override the background noise
wherever they may be," said audiologist Dean Garstecki, professor and
chairman of communication sciences and disorders at Northwestern
University in Chicago. "Depending on the level of background noise,
people have been known to crank up the volume to a level that could be
damaging to their hearing."
research, Wichita State University audiologist Ray Hull asked students
to take off their headphones in the name of science. Taking readings
with "a fairly sophisticated" sound level meter, Hull found typical
listening levels approaching 120 decibels.
it may be that some people just prefer to listen to their music as loud
as possible, Hull said, another factor is at work as well.
person can be listening at 60 percent volume, but then as the auditory
system adapts to the intensity of the sound, the perception of the
intensity is that it is becoming less, so the response is to continue
to turn the volume up," Hull said.
agree that it is important to guard against this desensitization by
minding the volume dial rather than simply trusting your ears.
good measure for how loud is too loud: "If you're standing across an
elevator cab -- that's about three feet away -- if you can hear someone
else's music, that person is giving themselves a hearing loss," said
The iPod's earbuds, the
essential accessory that have become almost as much of a status symbol
as the device itself, have been a particular focus for those expressing
concern about the potential for hearing loss. No less an eminence than
Pete Townshend of The Who warned fans in a post on the Internet earlier
this month that long-term use of headphones at loud volumes can lead to
the kind of hearing loss that he has experienced in recent years.
generally dismiss Townshend's assertion that his hearing loss is due
more to headphone use than with performing for four decades in a
notoriously loud rock band. But there is reason to believe that
listening to music through earbuds is less safe than, say, sitting
across the room from a set of stereo speakers.
listening to music on a home stereo system, Mason said, "I could be
sitting several feet away from the sound source, so the sound
dissipates in the environment and isn't directly funneled into my ear.
With foam earphones there is still some dissipation of the sound. When
you wear an earbud, it's fitting right down into your ear canal."
basically a matter of physics," noted Fligor, that earphones that are
smaller and closer to the ear produce higher sound levels. But he is
quick to add that there is no evidence that earphones actually cause
people to listen at louder volumes.
earbuds fit over the outer ear canal, the basic models do so without
blocking out background noise, meaning users often have to turn up the
volume to hear music over ambient sound. Audiologists say those hoping
to keep the volume down might want to upgrade from the earbuds that are
packaged with personal stereo systems.
headphones come in two main types: in-the-ear, noise-attenuating
earphones that work like earplugs to passively block out ambient sound,
and noise-canceling headphones that actively capture and remove
background noise. Some of Fligor's research has been funded by Etymotic
Research Inc., which makes noise-attenuating earphones.
course, these headphones tend to be expensive: Eytmotic's product for
iPods costs $149, according to the company's Web site. Bose's widely
advertised Quiet Comfort 2 noise-canceling headphones cost $299.
limiting the amount of background interference, noise-reducing
earphones can help personal stereo system users enjoy the listening
experience while keeping the device's volume down.
those who can manage it, experts agree, there is a happy space at about
65 to 70 decibels, the level of normal conversation. At that level, a
person could listen indefinitely without worrying about contributing to
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LOAD-DATE: January 17, 2006