Palatine resident Tom Thunder used to know his son had arrived home from his job at PetsMart by the sound of the garage door opening. After the teenager had a bass boost installed in the trunk of his car, Thunder says, “we could hear the music playing before we ever heard the garage door.”
Today’s world is all about noise.
In our grandparents’ era, people might have complained about the dang racket a rooster would make at sunrise or the shrill disturbance of an occasional siren.
Now, especially in large metropolitan areas, youngsters are exposed to a never-ending assault of sound. Much of the ear-piercing noise begins early, with the loud rattles, rings, blasts and bangs of children’s toys. Adolescents and teenagers are exposed through highly amplified music at home, in the car or at rock concerts as well as through the daily use of cranked-up personal listening devices.
“Yes, noise is a problem in a lot of areas,” says Thunder, an audiologist and noise control engineer who teaches at Rush-Presbyterian-St. Luke’s Medical Center and Northern Illinois University. “For example, there’s concern about the loudness at which theaters play movies.”
He notes that when the producers sent copies of the recently released movie “U-571” to theater owners, they asked them to play it at levels of more than 85 decibels to be sure the audience would experience all the special effects.
Decibel units, which measure sound, increase exponentially; a 10-decibel difference indicates a tenfold increase in loudness. Any continuous sound above 85 decibels is considered potentially damaging to hearing, and long exposure to noise above 90 decibels can cause hearing loss.
Besides movie soundtracks, other potentially loud noise producers are computer and video games and music-related products.
“There’s been a huge increase in stereo/audio products for the car, with the majority of consumers being teenagers,” says Thunder.
Audiologists are increasingly concerned that all this external commotion is leading to a rise in noise-induced hearing loss among the young. Yet cause-and-effect changes in hearing due to external noise are difficult to prove, research scientists say.
Noise-induced hearing loss results from damage to the ear’s hair cells, which lose their ability to function. The first hair cells affected are those associated with high frequency sounds, which are located at the base of the ear’s cochlea in the Organ of Corti.
High-frequency sounds are the first to be lost through noise pollution, yet 50 percent of the hair cells can die without a detectable loss of hearing. Therefore, much of the damage to a person’s hearing can occur long before he or she notices it.
Hearing isn’t lost through short bursts of loud sound, but with time and prolonged exposure to excessive noise levels.
“The severity of hearing loss is dependent upon two things,” says Dr. John Leonetti, an ear-nose-and-throat department specialist in otology and neurotology at Loyola University Medical Center in Maywood. “Number one, how loud the music is that they’re exposed to and, number two, the duration of the loud sounds. Most ears can tolerate short bursts of noise greater than 90 decibels, but if it starts accumulating to an exposure of six to eight hours a day, every day, the degree of injury to the inner ear is just about exponential.”
Leonetti says he has seen a fair number of patients with hearing loss at a younger age, particularly boys in their late teens who began playing rock music at a young age.
“It’s real difficult to get these young people to protect their ears because it’s uncool for a rock star to wear ear plugs,” he says.
Elliott Berger, senior scientist for auditory research at E-A-R, an international manufacturer of hearing protection devices, who leads one of three accredited hearing protection research laboratories in the United States, says there aren’t a lot of well-controlled studies on noise-induced hearing loss in children so it’s easy to overreact regarding music.
“First, the most hazardous non-occupational noise exposure people experience in our country today is shooting weapons,” he says. “You should never do it without wearing ear protection. When riding a snowmobile you also should have hearing protection. With music, it’s a little more problematic.”
Berger makes it a habit to measure sound when he attends concerts. While attending a recent three-hour performance by Santana at Deer Creek, a concert venue in Indianapolis, Berger measured the sound at 105 decibels while sitting in Row 18.
“That sound could be 115 decibels in the first two rows,” he said. “The 105 decibels could be hazardous if you’re exposed to it for more than 7 1/2 minutes. That’s based on a daily exposure five days a week, 250 days a year. So the situation is dramatically different for the performers than it is for concertgoers.”
Leonetti says that for children exposed to music or other recreational noise at sound levels of 50 to 60 decibels, the risk of significant hearing loss is extremely low. But if the intensity gets up to 80 to 90 decibels for six to eight hours a day, the risk is significantly higher.
“If a child is determined to make it as a musician, the most important thing is to limit the loud noise exposure to one or two hours a day,” he says. “You also should have some type of sound pressure measurement to determine the intensity of the music in your studio or garage.”
Although Tom Thunder acknowledges that noise-induced hearing loss in children is hard to prove, he believes it’s prudent to pay attention to your kids’ noise exposure and to educate them as to the permanent, irreversible hearing damage chronic loud noise can do.
“Hearing loss due to noise occurs much more rapidly during the initial 5 to 15 years of exposure than it does in the latter years of life. So the people with the most to lose are the younger ones,” he says.
It’s important to watch for signs that a child’s noisy environment may be doing harm.
“My son went to a concert last summer and he came back saying, `Wow, it was loud!’ ” says Thunder. “I asked him what his experience was after that and he said he had ringing in his ears. I told him that was Mother Nature’s way of telling him that he damaged his hearing.”
Anyone exposed to prolonged loud noise who then experiences a ringing in the ears or a muffling (as if someone talking to you sounds like they’ve got mashed potatoes in their mouth) has suffered a temporary hearing loss.
“That ringing, hissing or humming in your ears is called tinnitus,” says Berger.
“It’s like a sunburn on your skin, because the ear has been irritated and overworked. If this happens on a regular basis, chances are you’ll experience permanent hearing loss.”
“You experience what we call temporary threshold shift,” explains Alison Kaye, director of audiology services at Illinois Masonic Medical Center, Chicago. “If you had your hearing tested after a loud concert, it would show a hearing loss. That’s temporary.
Eventually, the hair cells relax and come back to working the way they’re supposed to. But if you do that over time, the hair cells aren’t going to make that recovery.”
It’s the same for children who spend a lot of time at noisy arcades, says Kaye. “Some of them probably are exposed to noise levels upward of 100 decibels.”
So how do parents test a child’s noise exposure for excessive loudness?
“First, a bad test is, `I hear the sound through my child’s earphones. It must be too loud,’ ” says Berger. “In this case your perception is heavily controlled by the noise around you.”
The better test is, if you’re in a noisy environment, or your child is creating a noise with his or her earphones, and it’s loud enough that at arm’s length you have to shout to be heard, then it’s probably 85 decibels or louder. Whether the 85 decibels is caused by noise in the space in which you stand or by the earphones on the child’s ears, the effect is the same. Eighty-five decibels is the point above which regular exposures are likely to cause hearing loss for a fair proportion of the population.”
Kaye suggests that parents look for signs from their children that something about their hearing isn’t right. Are they turning the television volume louder than they used to? Does the child say “What?” or “Huh?” frequently?
Although hearing screenings are mandatory in Illinois schools, Thunder recommends that children be given a professional audiological exam at about age 11.
“We run a pure tone audiogram where we measure people’s hearing thresholds at each of eight or nine different frequencies. The telltale sign is when there’s a drop in hearing at around 4000 hertz. We can distinguish for the most part a person whose hearing has been damaged by noise compared to other causes.”
In addition, Thunder recommends that children who play instruments invest in hi-fi earplugs.
“We’ve made some measurements of a simple clarinet at ear level and the sound is over 85 decibels, even if it’s played relatively softly,” says Thunder. “Combine that with a whole band of kids and you have a lot of, uh, sound.”
EARPLUGS NOT FOR ADULTS ONLY
If your child frequents loud concerts, noisy sporting events or practices instruments for long hours in a closed environment, it may be wise to push earplug use.
“A lot of kids don’t want to wear hearing protectors when they go to concerts because they do tend to change the characteristics of the music,” says Tom Thunder, an audiologist and noise control engineer who teaches at Rush Presbyterian St. Luke’s Medical College and Northern Illinois University. “Most hearing plugs reduce the sound in the high tones more than they do in the low, so they muffle the sound.”
The best earplugs for noise reduction are foam, says Elliott Berger, who researches the devices and is senior scientist for auditory research at E-A-R, an international manufacturer of hearing protection devices. “Foam is more comfortable and protective. There also are earplugs on the market designed to block less sound, but they do so in a way that’s a high fidelity type of attenuation. With these, you get the same type of noise reduction regardless of the pitch of the sound you’re listening to, so instead of sounding muffled, the sound is crystal clear.”
Foam earplugs can be purchased for as little as $2 for three pairs. Be sure to buy those with an NRR, or noise reduction rating. Earplugs without an NRR aren’t designed to block noise. Hi-fi earplugs cost between $12 and $15 a pair at music outlets. But that’s a small price to pay compared to hearing aids if your hearing is irreparably damaged, says Berger.
