Millions of Americans continue to risk losing their hearing each day, warns audiologist

May is Better Hearing Month, but millions of Americans are continuing to needlessly risk losing their hearing each day, warns audiologist Dr. Cindy Beyer.

"Almost all hearing loss is due to the aging process or to noise, but only noise-induced hearing loss can be prevented," says Dr. Beyer, senior vice president of HearUSA, (Amex: EAR) a nationwide provider of hearing care and hearing aids.

Ten million Americans have already suffered irreversible hearing damage from noise and another 30 million are exposed to dangerous levels of noise each day, according to the National Institute on Deafness and Other Communication Disorders  (NIDCD).

"Noise-induced hearing loss usually develops gradually, often over a period of many years. The damage done to hearing is related to noise levels and the durations of exposure," says Dr. Beyer.

She noted that a single acoustic trauma, such as that caused by a shotgun blast, can result in permanent hearing loss -- or in temporary hearing loss, which may be followed by partial or total recovery. "Sudden hearing loss always requires prompt medical attention," says Dr. Beyer.  

"The good news," says Dr. Beyer, "is that noise-induced hearing loss can be prevented by recognizing and avoiding potentially damaging noise whenever possible, and using effective hearing protection, such as earplugs or earmuffs, when exposure is unavoidable."

The unit used to measure sound is a decibel: While a whisper may be 30 decibels, and normal conversation 60 decibels, a hair dryer may be 90 decibels and a leaf blower 110 decibels. An increase of 10 on the decibel scale means the sound is ten times more powerful.

Dr. Beyer cautions that, over time, prolonged unprotected exposure to noise levels above 85 decibels can cause permanent hearing loss by damaging the sensitive cells in the inner ear that convert sound energy into electrical signals that travel to the brain.

The NIDCD warns that regular exposure of more than one minute to 110 decibels risks permanent hearing loss and recommends no more than 15 minutes of unprotected exposure to 100 decibels.

The Sight and Hearing Association estimates that unprotected hearing can be damaged in 7.5 minutes at a rock concert (120 decibels), four hours on a motorcycle or when using a power saw (95 decibels), 15 minutes at a stadium football game (115 decibels) and eight hours in truck traffic (90 decibels).

In the workplace, the National Institute for Occupational Safety and Health (NIOSH) has determined that the safe limit for noise exposure at 85 decibels is eight hours a day. However, each three decibel increase in noise cuts the safe exposure time in half (four hours at 88 decibels, and two hours at 91 decibels).

If there are symptoms of hearing loss, including sounds that appear distorted or muffled, a ringing in the ears, a feeling of fullness in the ears and difficulty understanding speech, a hearing test is essential, says Dr. Beyer.

Which noises to be wary of? Dr. Beyer says she agrees with the NIDCD's advice to avoid noises that are "too loud" and "too close" or that last "too long."

"Today's hearing aids are smarter, smaller and more comfortable than ever and, with proper professional hearing care support, they can benefit 95 percent of all those with hearing loss. However, there is no substitute for prevention, and noise-induced hearing loss is 100 percent preventable," says Dr. Beyer.