In Oregon and nationwide, audiologists are seeing more ears harmed by loud noise at younger ages. Damage once common in 60-year-olds increasingly hits 45-year-olds, who are sprouting hearing aids like ear hair.

And many children show signs of hearing loss not seen in previous generations. A 1990s federal survey, the first of its kind, estimated that 5.2 million children have measurable hearing damage from noise, about 1 in 8 schoolchildren. Researchers are waiting for updated survey results.

But audiologists at four big Oregon clinics are seeing signs of a growing problem. In response, Oregon Health & Science University and Oregon Museum of Science & Industry experts crafted an education program called "Dangerous Decibels," which they hope to spread to children statewide.

"The number of kids with hearing loss is dramatically increasing. And the culprit seems to be noise," said OHSU audiologist Billy Martin, Dangerous Decibels' scientific director.

These children generally don't need hearing aids now. But doctors are uncertain -- and rarely optimistic -- about their sonic future.

"Basically, what has happened is we have stepped up the timetable for how soon hearing loss is going to occur in them," said Brian Fligor, an audiologist with Children's Hospital Boston. "If they don't change their behaviors, they may be paying the piper for a long time."

For decades, industrial work and military service caused the most harm to hearing. Today, the growing problem is loud leisure, from hunting to woodworking. Blaring music, from yesteryear's Zep show to yesterday's crunk download, gets much of the blame. Enter popular digital music players such as the iPod, which can pour uninterrupted hours of music into the ear.

"I listen to it loud. All the way up," said Jefferson Rillera, a Benson Polytechnic High School senior and iPod fan. "I'm used to music like that."

That alone worries hearing experts. And many young people layer on a soundtrack of computer games, movies, TV, lawn mowers, car stereos and other modern racketeers that -- without temperance or earplugs -- pave the road to old, dull ears.

More than a fifth of 1,419 youngsters informally surveyed at OMSI's Dangerous Decibels exhibit said they fired a gun in the past year. More than half reported riding in cars with loud stereos, and 34 percent went to a concert.

"I had about five kids go to the Stones concert" this month, said fourth-grade teacher Eadi Popick, who had Dangerous Decibels volunteers talk to her Riverdale Grade School class last week.

Personal music players draw more concern as they grow more popular. Nearly 90 percent of teens surveyed at the OMSI exhibit had recently used some kind of stereo headphones.

"I think that a large part of it is these MP3 players and iPods," said Teri Hall, audiology supervisor for Kaiser Permanente Northwest and a mother of two. "I tell my kids, when they're sitting in the back seat, if I can hear that music and you've got the inserts in your ear, it's too loud."

The basic problem is the same one behind the obesity epidemic: Human society evolves faster than the human body can.

"Our ear was not designed for these things from the industrial era -- guns, power tools, Metallica concerts," said Robert Folmer, an Oregon Health & Science University hearing expert.

The inner ear bristles with thousands of tiny cells that look like pickles with pompadours. Sounds 100 times softer than a whisper can set these "hair cells" vibrating, sending signals to the brain. Louder sounds make bigger vibrations that can bend and break the hairs, which the body can't repair or replace. The louder the sound, the faster it can cause permanent damage. A power lawn mower can cause mild damage in 15 minutes, a loud rock concert in 15 seconds.

An estimated 28 million U.S. residents -- about 1 in 10 -- have hearing problems, and at least a third of those can blame noise-induced hearing loss.

The damage starts subtly, with the outermost cells that detect higher pitches. People may have trouble conversing with background noise, as in a moving car or busy restaurant. Over years, many people grow to need hearing aids. Some start hearing frequent ringing, called tinnitus. Severe hearing loss can cause work problems, social withdrawal, isolation, anxiety and depression.

"I often describe progressive hearing loss as being in a brightly lit room, and someone is very slowly turning down the dimmer over time," Salem Audiology Clinic's Scot Frink said.

Traditionally, that damage hit senior citizens or middle-aged laborers such as soldiers, musicians and timber workers. The government has regulated workplace noise for years, so hearing loss should be decreasing. Instead, Frink said, "the percentage of baby boomers that have hearing loss is higher than the generation that preceded them." Why? "Led Zeppelin. Rolling Stones. Pharmaceutical experimentation."

Many baby boomers still don't need hearing aids. But increasing numbers of them do, and they are less shy about wearing aids than previous generations, Eugene Hearing & Speech Center audiologist Peter Succo said.

The good news is that hearing loss is largely preventable, Martin said. The basic rules are to turn down or move away from sounds that make your ears ring or hurt or that interfere with normal conversation. And wear plugs or muffs while mowing the lawn, woodworking, hunting and at concerts -- anything above 85 decibels, about the volume of traffic.

That can be tough with personal stereos, since manufacturers don't mark volume dials in decibels. But Fligor tested more than a dozen CD players and found the top volumes ranged from 91 decibels to 121 decibels. The latter can cause hearing damage in 7 seconds.

In general, Fligor said, stereo headphones are safe for up to one hour of listening with CD players set at 60 percent of maximum volume. He is finishing a similar study on digital music players, which he said seem to be "in the same ballpark as the CD players," including the 60 percent-60 minute rule.

An Apple official refused to comment on hearing and iPods, but the users manual says the device can hit 104 decibels, enough to cause mild damage after 6 minutes. Apple had to modify the iPod for France, which limits consumer products to 100 decibels. The United States has no such rule. The iPod manual warns generally that "permanent hearing loss may occur if earbuds or headphones are used at high volume."

While ear plugs and advice to "turn it down" may have limited cool, audiologists say prevention should be weighed against the alternative.

"Quite honestly," Succo said, "that's a lot easier than wearing a hearing aid down the road."

Source: http://www.tmcnet.com/usubmit/2005/nov/1209712.htm