Noise Induced Hearing Loss and Its Prevention (cont.)

Hearing loss usually develops over a period of several years. Since the hearing loss is painless and gradual, many people may not notice it. What someone may notice is tinnitus, which is a ringing or another sound in the ear. The tinnitus could be the result of long-term exposure to noise that has damaged the hearing nerve. Or, a person may have trouble understanding what people are saying or may hear everyone as mumbling. Such hearing difficulties are especially apt to occur when one is trying to hear in a noisy place such as in a crowd or at a party. These difficulties could be the beginning of high-frequency hearing loss.

A typical hearing test (audiogram) of a person with noise induced hearing loss will initially show only a high frequency loss at 4000 Hz. (Hertz or Hz is the measure of sound frequency or pitch. Four thousand Hz is high frequency, while 250 or 500 Hz would be low frequency). With continued noise exposure and hearing loss, the audiogram will show a broader loss to include lower (deeper) frequencies.

Noise-induced hearing loss will almost always affect both ears equally, but in some situations, especially with firearm usage, it may be worse in one ear than in the other. For example, firing a rifle tends to injure the ear opposite the side of the trigger finger due to the shadow (blocking the sound) effect of the shooter's head.

If a person has any of these symptoms that suggest hearing loss, he or she should consult a physician with special training in ear and hearing disorders (an otolaryngologist or otologist). This type of doctor can diagnose hearing problems and recommend the best way to manage them.

While there is no cure for noise-induced hearing loss, there is some promising research being done. The National Institute on Deafness and Other Communication Disorders (NIDCD) is looking at the use of antioxidants to prevent hearing loss and restore hearing. NIDCD-funded researchers have shown that aspirin and vitamin E can reduce hearing loss if used before exposure to loud noise.

Researchers at the University of Michigan used vitamins A, C, E and magnesium prior to loud noise exposure to prevent hearing loss in animal studies. Studies on people are in progress.

For examples of sounds measured in dBs, The American Academy of Otolaryngology-Head and Neck Surgery provides an Interactive Loudness Scale.

Reference: American Academy of Otolaryngology-Head and Neck Surgery

Previous contributing editor: Leslie J. Schoenfield, MD, PhD

Last Editorial Review: 7/21/2009

Source: MedicineNet.com
http://www.medicinenet.com/noise_induced_hearing_loss_and_its_prevention/article.htm