Conventional wisdom would have us believe that hearing loss is as inevitable as gray hair and age spots. But research has shown that excessive noise exposure is one of the leading causes of ear damage. ““About 75 percent of hearing loss in the typical American is caused not by the aging process alone,’’ says William Clark, a senior scientist at the Central Institute for the Deaf in St. Louis, ““but by what you’ve done to your ears throughout your lifetime.’’ While few of us will ever endure the long-term beatings of a punker or a pilot, we are all in danger of permanently injuring our hearing without even realizing it. More than 20 million of us are exposed on a regular basis to noxious noise levels–and the effects are beginning to show. ““We’re seeing evidence of an increase in hearing loss at younger ages,’’ says Laurie Hanin, director of audiology at the League for the Hard of Hearing in New York City. ““We believe it’s due to an increase in noise in the environment.''
Noise damages our ears in two ways. It can strike in an instant, causing what is known as acoustic trauma. One blast from a high-powered hunter’s rifle can rip apart the ear’s inner tissues, leaving scars that permanently dampen hearing. It can also develop insidiously over a period of decades in what is called noise-induced hearing loss, or NIHL. Dangerous noise levels attack the inner ear’s 16,000 hair cells, the tiny workhorses that transport airborne vibrations to our brain, where they’re decoded as speech or screech or–spare us all–the wail of a car alarm. Those hair cells do spectacular work, but they’re incapable of regeneration. By the time we get the signal that something is wrong–a ringing in the ears, a muffling of sounds–some of the cells may have died. ““Your ear doesn’t bleed after a rock concert or a shot of fireworks,’’ says Clark. ““That’s why noise is a bigger hazard than it seems.''
Consider the decibel (dB) count a temperature reading for the ear, with 85 dB marking the fever point for safe, unlimited exposure. Washing machines and vacuum cleaners (both less than 85 dB) aren’t likely to cause harm–even if you listen to them every waking hour. But as dB levels rise to 85 and beyond, our ears enter a danger zone that worsens with length of exposure. Your ear can safely handle two hours with a power drill (100 dB), but not more than 30 minutes in a noisy video arcade (110 dB). Every 10-decibel increase on the sound scale represents 10 times more ear-battering noise. It will come as no great shock to parents that a screaming child (90 dB) rings in louder than a typical alarm clock (80 dB). And few commuters will be surprised to learn that a subway platform (at 100 dB) is considerably noisier than a busy city sidewalk (80 dB).
City folk have long complained about noise; New Yorkers ranked it the No. 1 problem at the turn of the century and still do today. But even the suburbs are no longer quiet escapes from aural mayhem. They’ve become open-air stages for the 1990s din of leafblowers and ““boom cars,’’ those rock concerts on wheels. ““People are finding they’re no longer able to run away from it,’’ says Les Blomberg, head of the Noise Pollution Clearinghouse in Montpelier, Vt. Even picturesque Vermont has acoustical battles to fight. The latest menace is a 100 dB street sweeper–Blomberg measured the noise level himself–that rumbles through Montpelier at 4 a.m.
No matter where you live, there are practical steps you can take to protect your ears. For roughly the cost of bus fare, anyone can buy a pair of drugstore earplugs. Their noise-reduction levels (ranging from about 20 dB to 30 dB) and styles (foam, silicone and wax) aren’t all that important. What matters is that you wear them whenever you’re in a noisy environment. Just don’t resort to cotton–it won’t stop sound waves from attacking your ears. When you’re not sure whether to bother with the plugs, take a simple noise test: if you’re three feet away from someone and have to raise your voice to be heard, it’s time to put them in. Try giving your ears a rest, too. After several hours in a boisterous baseball stadium, it’s wise to wait a day before heading to a rock club. And don’t forget about the kids. Toy rattles can hit 110 dB, and children’s electric guitars reach even higher.
Though you can’t repair a noise-damaged ear, treatment options for the hearing impaired are improving markedly. Conventional hearing aids have never been all that popular: only about 20 percent of the 28 million Americans with hearing loss wear them. Most people can’t put up with the pumped-up volume of background chatter, and no one likes having to adjust the volume when moving from one room to another. But a new generation of fully digital hearing aids, which cost about $3,000, now offer more sophisticated alternatives. Their tiny computer chips filter sound into bands, matching them against a patient’s personal hearing-loss profile, softening some pitches and amplifying others.
Dr. Barry Freeman, an audiologist in Clarksville, Tenn., says patients using digital devices report 85 to 90 percent satisfaction, compared with only about 60 percent for conventional wearers. Not all audiologists are embracing the pricey new technology. Dr. Aaron Thornton, director of audiology at the Massachusetts Eye & Ear Infirmary, says the new circuitry also adds new noise. And he’s concerned about price: digitals are at least twice as expensive as the average conventional device and most insurers won’t cover the cost. But for people like Paul Malkin, a 15-year veteran of hearing aids, there’s nothing better. ““The relief is like someone lifted a stone off my head,’’ he says.
If you’re careful, you may never need to resort to this technology. Efforts at prevention are sweeping the country. Kathy Peck felt so strongly about educating others that she started Hearing Education and Awareness for Rockers (HEAR) in San Francisco. HEAR is recording a CD called ““Wear Your Damn Ear Plugs,’’ which will combine hip tunes with a warning about loud music. Hearing specialists are in the act as well, giving out earplugs like pediatricians’ lollipops. ““I keep boxes and boxes of them,’’ says Freeman. ““We hand them out like they’re candy.’’ They may not taste as good–but your ears will be ringing with joy. ^
Any noise louder than 85 decibels* is a potential hazard to your hearing. The louder the sound, the faster it causes harm. Some common culprits:
Noise leve; Safe Source in Decibels Exposure Gunshot 140 none Jackhammmer 130 3.8 minutes Rock Concert 120 7.5 minutes Power drill 100 2 hours Lawn Mower 90 8 hours Vacuum cleaner 80 no limit
*Each 10-decibel increase represents a tenfold increase in sound energy
Hearing involves the passage of sound waves through the cochlea. Vibrations cause tiny hairs to brush against the tectorial membrane, triggering electrical impulses to the brain. Loud or prolonged noise can permanently damage the delicate hair cells.
