What Causes Hearing Loss
What Causes Hearing Loss
Noise, not age is the leading cause of hearing loss. Unless you take steps now to protect to your ears, sooner or later many of you — and your children — will have difficulty understanding even ordinary speech. Millions of Canadian, already have permanent hearing loss caused by the everyday noise that we take for granted as a fact of life.
“The sad truth is that many of us are responsible for our own hearing loss.”
While there are myriad regulations to protect people who work in noisy environments, there are relatively few governing repeated exposure to noise outside the workplace: portable music devices, rock concerts, hair dryers, sirens, lawn mowers, leaf blowers, vacuum cleaners, car alarms and countless other sources.
The ears are fragile instruments. When sound waves enter the ear, they cause the eardrum to vibrate. The vibrations are transmitted to the cochlea, in the inner ear, where fluid carries them to neatly organized rows of hair cells. These in turn stimulate auditory nerve fibers, each attuned to a different frequency. These impulses travel via the auditory nerve to the brain, where they are interpreted as, say, words, music or an approaching vehicle.
Damage to this delicate apparatus results from both volume and length of exposure to sound. Very loud noises, or chronic exposure to sound even when it is not particularly loud, can wreak havoc on hair cells, causing them to become disarranged and to degenerate.
We are born with a fixed number of hair cells; once they are dead, they cannot be replaced, and auditory sensitivity is permanently lost. Usually, sensitivity to high-frequency sounds is first to go, followed by an inability to hear the frequencies of speech.
Sound volume is measured in decibels (dB), and the level at which noise can cause permanent hearing loss begins at about 85 dB, typical of a hair dryer, food processor or kitchen blender.
But even noisier than many of these is the maximum output of some portable music players, which can exceed occupational safety levels and produce sound levels in the ear on a par with that of a jet taking off. If you listen to music with earbuds or headphones at levels that block out normal discourse, you are in effect dealing lethal blows to the hair cells in your ears.
In general, if other people can hear what you’re listening to, the volume is turned up too high. Many times I’ve had to change my seat on the subway or bus because the rider next to me was using a music player as if it were a boombox.
Some portable listening devices come with the ability to set a maximum volume, which may be worth the added cost to parents concerned about protecting their children’s ears.
At a given volume level, earbuds deliver higher noise levels than over-the-ear headphones. If earbuds are used. Alternatively, when you are alone and not at risk of missing important environmental cues, like an approaching vehicle, consider using noise-canceling over-the-ear headphones that block out background noise and enable you to listen at a lower volume.
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