"I don't make it too loud. I try not to because it hurts your ears eventually," the 18-year-old Toronto student says after shutting down her iPod and removing her ear buds.

"I want my hearing. I want to be able to hear for the rest of my life . . . I don't listen to very loud music a lot."

Vaserman's take on protecting her sense of sound would be music to the ears of hearing experts, who say cranking up the volume on portable music players and blasting it directly through those tiny headphones is setting the stage for an epidemic of early hearing damage.

"Lots of children and young adults are getting noise-induced hearing loss," says Bob Harrison, an audiologist at Toronto's Hospital for Sick Children.

Surveys have found 15 per cent of North American youth ages six to 19 have reduced hearing because of too much exposure to noise.

That percentage is bound to get higher as more and more young people plug into sound, whether it's from iPods or MP3 players, cellphones or video games, hearing specialists say.

Coupled with the din of modern-day society -- from street traffic to machinery to noisy clubs and even school cafeterias -- the assault on our hearing often seems deafening.

"The additional problem is that when these children get into a noisy environment and they're wearing these devices," Harrison says of ear buds. "They have to put the sound up even louder to counteract the environmental sound.

"And this is when the levels become really elevated."

Noise-induced hearing loss results from the cumulative onslaught of sound on tiny hair cells in the delicate mechanisms of the inner ear, located behind the ear drum.

Hair cells -- so called because of hair-like filaments growing from them -- act as mini receivers, moving as sound washes over them and transferring signals through the auditory nerve to the brain.

Think of sound as wind and hair cells as clumps of grass: a low to moderate sound ruffles the shoots like a soft breeze; high-decibel noise is like a hurricane-force gale, violently tossing the blades in all directions or laying them flat.

"The hair cells can't cope with loud sounds and they become damaged," Harrison says. "And when they become damaged, they die."

While humans are born with about 15,000 of these cells, their number is finite, he says. "Hair cells do not regenerate. They don't recover. Once they're dead, they're gone."

In other words, the loss of hearing is permanent.

One sign of damaged hearing is loud ringing in the ears after leaving a noise-filled venue, such as a concert or sports event. Tinnitus, a continuous ringing, swooshing or buzzing in one or both ears, also signals a hearing problem.

There's no way to reverse hearing loss, which usually begins in the high-frequency range, making conversations hard to make out in noisy situations.

But further deficits can be prevented by turning down music to moderate levels (below 85 decibels) and limiting listening time. Experts also advise wearing ear plugs at concerts (they don't block the music, just muffle the volume) and while riding ear-splitting machines such as motorcycles and snowmobiles.

While some hearing loss is inevitable as we grow older, usually becoming noticeable in middle age, Harrison says repeated exposure during childhood and adolescence to blaring music and other high-volume sounds is hastening the onset of age-related hearing problems.

"What we're finding scientifically is that noise-induced hearing loss actually makes this hearing loss of old age come earlier," he says. "Now we're finding that instead of the hearing loss starting at 50, it will start at 40, 30 or even 20."

By Sheryl Ubelacker
http://lfpress.ca/newsstand/Today/2005/10/24/1275809-sun.html