By LEE BOWMAN
Scripps Howard News Service
March 14, 2006
The survey of 301 teens and 1,000 adults nationwide, which was done for the American Speech-Language-Hearing Association, also found that 47 percent of adults reported at least one symptom of hearing loss.
Although it's not clear from the poll what's causing the symptoms, researchers from Zogby International found that the listening habits of both students and adults are potentially harmful to hearing health.
Students were more likely than adults to report such problems as needing to turn up the volume on their TV or radio to be able to hear, experiencing ringing in their ears, and having to ask a conversation partner to repeat something because they didn't hear it.
Two-fifths of teens and adults set the volume at "loud" on their Apple iPods, with students twice as likely to play it "very loud" - 13 percent versus 6 percent of adults. But 71 percent of the students said they crank up the volume when they listen to sound from a laptop computer with earphones, compared to just 15 percent of adults.
Adults tend to use iPods and MP3 players for longer periods of time than teens, perhaps reflecting commuting habits, while more than half of teens say their typical session on a laptop lasts one to four hours.
"Louder and longer is definitely not the way to use these products," said Brenda Lonsbury-Martin, chief of science and research for the association, during a forum to discuss the threat of hearing loss from portable devices. "Eventually, that becomes a recipe for noise-induced hearing loss, which is permanent."
More than 30 million Americans have significant hearing loss, and at least a third have hearing loss as a result of exposure to noise.
Experts say that music and other sound at volumes of 85 decibels and higher is sufficient to cause permanent hearing loss. A recent test of nine devices - including music players, laptops and pocket computers - by the ASHA found that every one topped 105 decibels at full volume, and all but one exceeded 85 decibels at half volume.
Of particular concern to researchers is the growing use of small earpieces or earbuds with audio devices that are able to store many hours' worth of music.
"The combination of high-signal intensity and long listening duration is a proven formula for permanent, irreversible hearing loss," said Dean Garstecki, an audiologist and professor at Northwestern University. He is particularly concerned about the effect of the earbuds, since they are less efficient at blocking outside noise and tend to encourage users to crank up the volume than headphones that cover the entire ear.
The survey found that only about 1 in 5 students and adults uses the earmuff-style phones.
Brian Fligor, a hearing researcher at Children's Hospital in Boston, said his research on CD players suggests that listening at no more than 60 percent of top volume for one hour a day or less would probably be safe with traditional earphones, but said sound should be set lower if earbuds are used.
He and colleague Terri Ives of the Pennsylvania College of Optometry have been studying listening habits to determine if some people are naturally disposed to listen at high volume.
"So far, we've found that when it's very quiet, the majority of people listen at safe levels," although they may turn up the volume if there's a lot of noise around them. "But even in the quietest room, some people (between 5 and 25 percent) set their music to high levels that might be risky if they listened for too long."
The association is already working with government officials and manufacturers about setting standards or guidelines for use of audio devices. "We need to develop ways for consumers to know when they are putting their hearing at risk when they are using these devices,'' said ASHA President Alex Johnson, a professor of audiology at Wayne State University in Detroit.
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