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December 15, 2003

Baby-boomer hearing loss

From: Charleston Post Courier (subscription), SC - Dec 15, 2003

Noisy past can cause problems

Of The Post and Courier Staff

About four years ago, Jim Mitchell started to realize that he was missing some of what was being said at business meetings and lunches. Mitchell, in his 40s, frequently had to ask his colleagues and friends to repeat what they said.

It was frustrating.

Diagnosed with moderately significant hearing loss, Mitchell says rock concerts from the 1970s may have taken their toll. He has what's referred to as "baby-boomer hearing loss."

Mary Anne Larkin, Mitchell's audiologist, says problems hearing sounds at higher frequencies are noise-induced. It involves trouble hearing high-pitched voices and soft consonant sounds such as P, S and T.

It's something that many who were born from 1946 to 1964 -- the baby-boomer generation -- are experiencing in their middle years. They are among the generation that is expected to live a longer, more active life because of better health. But their noisy past is causing problems.

"Already, there are more baby boomers suffering from hearing loss than ... people above 65," Larkin says. "We have seen an increase in hearing loss as a result of increasingly noisy lifestyles and noisy environments."

Hearing loss among baby boomers began to gain attention when President Bill Clinton was fitted with two hearing aids in 1999, Larkin says. He blamed his high-frequency hearing loss on rock bands, helicopters and screaming during campaigns.

Digital hearing aids such as his are suitable for those with mild hearing loss. They also can be worn inside the ear canal. Some of the hearing aids, which cost around $3,000, have microphones that help make conversation clearer, tune out background chatter and dampen noise such as traffic.

A National Center for Health Statistics survey has found those ages 46 to 64 have 26 percent more hearing loss than those in previous generations. In addition, a study focusing on Alameda County, Calif., for 30 years found people are losing their hearing earlier.

Experts often agree with Clinton that rock concerts are a cause. But they probably are not the only one.

Baby boomers' hearing losses could be caused by power tools, motorcycles, riding mowers and other noisy toys. Larkin says that as America ages, hearing impairment could become more prevalent and more severe than previously expected.

Mitchell has decided to try wearing a hearing aid to correct his problem.

"My career takes me in and out of manufacturing plants," he says.

The combination of background noise and hearing loss can limit the ability to converse efficiently and make it harder to conduct business.

The number of baby boomers among Larkin's clients is on the rise, she says.

They often regard even mild hearing losses as unacceptable and see treatment as a way of enhancing their lifestyles, she says. Mitchell's problem, difficulty hearing when there is background noise in group conversations and in restaurants, is fairly typical.

Some are getting help because they have higher expectations of themselves, Larkin says. Like Mitchell, they see hearing loss as a hindrance and treatment as important. Needing things repeated at work can be misinterpreted. "Treatment can bring about that competitive edge," Larkin says.

The boomer hearing problem is caused when hair cells of the inner ear, or the tissues that hold them, are damaged, according to the National Institute on Deafness and Other Communication Disorders.

Sound waves enter through the ear canal and strike the eardrum, causing it to vibrate. The sound passes on through a small opening into the inner ear. The vibrations then move through fluid in the cochlea (hearing portion of the inner ear), which contains hair cells. The fluid in the cochlea moves the top of the hair cells, which causes changes that produce nerve impulses. The nerve impulses are carried to the brain and interpreted as sound.

Once the tissue that holds the hair cells is damaged and the cells are stressed, hearing capacity is diminished, Larkin says. After a loud event such as a rock concert, regular hearing usually returns in fewer than 16 hours, but repeated exposure can cause permanent damage.

Noise-induced hearing loss is preventable, say Larkin and Dr. Paul Lambert, chairman of the department of otolaryngology at the Medical University of South Carolina. They recommend that people of all ages avoid unnecessary exposure to excessive noise, especially extended exposure.

Larkin suggests listening to music and television programs at a moderate level.

Noise in the industrial environment is well-controlled by Occupational Safety and Health Administration standards, they say. But many situations outside the workplace also call for wearing hearing protection.

Lambert has not seen evidence that baby boomers' hearing loss is any greater than that of previous generations. But boomers' affinity for noisier toys during leisure time may be working against OSHA's successes in controlling industrial noise.

Noise levels are measured in decibels, the unit of measurement for loudness, Larkin says. It can be as low as 0 and as high as 194.

A sustained level of noise at 85 decibels for eight hours would be considered the upper level of safe noise in most countries, Larkin says. The higher the decibel level an activity carries, the shorter amount of time a person safely can be engaged in it.

Ear pain can begin at 125 decibels, Larkin says.

The hum of the refrigerator is 40 decibels. Normal conversation is 60; city traffic and dial tones, 80; a clarinet, 92 to 103; the average Walkman on a middle setting, 94 decibels; power lawn mowers, 107 decibels; power saws, 110; symphonic music at peak, 130 to 137 decibels; amplified rock music four to six feet away, 120 decibels; and rock music at its peak, 150.

Noise levels that cause people to raise their voices to be heard during normal conversations have the potential to damage their hearing if they are exposed to it repeatedly, Lambert says.

"If there is ever a question about whether noise will be harmful, a person should use hearing protection," Lambert says. "The best option is an ear muff, and the second best is plugs inserted into the hearing canal."

While going to a concert every three or four months probably would not normally hurt a person's hearing, playing regularly in a rock band likely would.

"The hearing loss that results from noise has a very insidious onset," Lambert says.

A person can have a fair amount of loss without noticing it for a long time. At some point, the loss becomes noticeable. It takes only a little extra aging to make the difference. Exposure to noise in youth can accelerate the hearing loss that comes naturally with age. If a person did not have that early damage, the loss of hearing in middle age might not be as bad, he says.

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