Noise and hearing loss: a preventable disaster.
By day, John works as a pressman in a busy newspaper plant. On nights and weekends, he enjoys attending rock concerts, hunting and woodworking, among other things.
Unfortunately, what John may not realize is that each of these activities -- when done on a regular basis -- is noisy enough to pose a significant risk to his hearing.
Millions of Americans are similarly vulnerable to noise-induced hearing problems, as hearing loss can be caused by exposure to loud noise over a long period of time. Yet situations such as John's don't have to be hazardous. Excessive noise, although preventable, is the nation's primary cause of hearing loss.
In John's case, participation in a company hearing conservation program or a visit to his physician for referral to an audiologist would likely allow him to continue his work and hobbies without fear.
Noise as an environmental health problem has long been overlooked, as has its role in hearing loss as well as other disabilities. Many people may not realize that whenever noise is so loud as to make it difficult to communicate, or when they experience temporary hearing loss because of loud noise, they are ultimately endangering their ability to hear. To make matters worse, the effects of the different forms of noise encountered during the day -- at work, at home or while at leisure -- are cumulative.
Although excessive noise seldom causes deafness, it can be a major factor in partial hearing loss. Symptoms may disappear within 24 hours of exposure, but cumulative damage may be irreversible. There is no known medical cure and a hearing aid will only help somewhat.
Excessive noise causes hearing impairment by progressively damaging the sensory hair cells of the cochlea. Degeneration of the cells starts near the base of the cochlea, where high-frequency sounds are detected, but can eventually spread to the entire cochlea. Once destroyed, the hair cells cannot be replaced or repaired.
Continuous exposure to loud noise such as farm tractors, newspaper presses, rock drills, motorcycles, diesel trucks and jet planes carries a significant risk of hearing impairment. Even sounds like shouting in conversation, the noises of a blender or a garbage disposal have intensities loud enough to cause hearing damage. Recreational activities such as hunting, riding snowmobiles or listening to loud music pose additional risks.
The early stages of noise-induced hearing loss are often only detectable through hearing tests. Sometimes a person may report a ringing in the ears, muffling of sounds, discomfort or temporary hearing loss that diminishes shortly after leaving the source of the noise.
Industrial environments are among the most hazardous. They often expose workers to higher noise exposure levels than the standards set by the federal Occupational Safety and Health Administration. An industrial worker in Bath, Maine, lost 82 percent of his hearing after using an air-powered rivet gun to pound rivets into the steel hulls of ships for 30 years. He did not use ear protection devices.
Employers can prevent or minimize noise-induced hearing loss by implementing hearing conservation programs. The federal agency, OSHA, actually mandates such programs for companies with hazardous noise levels that are involved in interstate commerce, but many employers don't comply.
Hearing conservation programs usually involve monitoring noise levels, notifying and training employees, and regular testing. They should be conducted under the supervision of a physician or audiologist.
Workers exposed to noises close to or greater than the levels permitted on a daily basis by OSHA should be supplied with hearing protection. Ear plugs or ear muffs are very effective, and when used together, offer the best protection. Stuffing cotton balls or tissue in the ears helps somewhat, but is only about half as effective as either plugs or muffs.
A worker who wears properly fitted hearing protectors and participates in annual audiograms can feel well protected. For people who are self-employed or who are exposed to noise in an environment other than work, a family physician can arrange a referral to an otolaryngologist or audiologist for regular testing and/or protective devices.
In addition to preventing noise-induced hearing loss a hearing conservation program can identify other hearing disorders and refer those workers for further evaluation. Otologic disorders that are asymmetric, progress rapidly, and/or involve low-frequency threshold shifts are most likely related to factors other than noise.
Hearing problems can also be caused by viral infections, vascular disorders (such as heart conditions or strokes), head injuries, infections, tumors, heredity, otosclerosis, medication or age-related conditions. People with hearing difficulties should consult a doctor to determine that no serious medical condition is involved. An audiometric and otologic evaluation can help diagnose the specific cause.
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|Title Annotation:||includes related article on hearing and older people|
|Publication:||Nutrition Health Review|
|Date:||Jan 1, 1993|
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