Age-Related Hearing Loss

by Food and Drug Administration (FDA)

The popular notion that older people are "hard of hearing" is often true. Hearing loss occurs gradually in most people as they age. According to the National Institute on Deafness and Other Communication Disorders (NIDCD), part of the National Institutes of Health, about 1 out of every 3 U.S. adults between the ages of 65 and 75 has a hearing loss. The NIDCD further estimates that about half of people 75 and older have some degree of hearing loss.

"We are born with a set of sensory cells, and at about age 18 we slowly start to lose them," says Hinrich Staecker, M.D., Ph.D., director of the otology and neurotology program at the University of Maryland Medical Center in Baltimore. But because age-related hearing loss, called presbycusis, progresses so slowly, most people don't notice any changes until well after age 50.

There are exceptions. Nancy McKinney was in her 40s when she was diagnosed with mild, age-related hearing loss. Now 51, the college English professor from Taylorville, Ill., remembers that she kept telling her students in her classes to speak up. She also recalls constantly turning up the volume on her TV. Hounded by family and friends, McKinney eventually sought the advice of one type of hearing specialist — an otolaryngologist.

"My family was driving me nuts," she says. "But the main thing was I knew that I couldn't hear." Because her hearing loss was mild, she was told that she did not need a hearing aid at that time.

Presbycusis, which the NIDCD says usually affects both ears equally, is most commonly caused by gradual changes in the inner ear. As people age, structures of the ear can become less responsive to sound waves, contributing to hearing loss. Staecker says that early, undetected hearing problems can compound hearing loss brought on naturally by aging.

Hearing problems can make it difficult for older people to hear doorbells, car horns, and alarms. Hearing loss also can make it hard to understand and follow a doctor's advice or respond to warnings. Its effect on speech communication can reduce a person's physical, functional, emotional, and social well-being. Isolation and depression often accompany hearing loss. All of this can be frustrating, embarrassing, and even dangerous.

Without being aware of it, people with presbycusis may make small adjustments over time, for example, standing closer to someone who is speaking or turning up the TV volume, that allow them to perceive the sounds and cues they otherwise would miss. At some point, though, the loss may become so severe that these adjustments become ineffective.

The good news is that there are ways to compensate for age-related hearing loss. There are devices to help people hear and communicate more easily, including hearing aids and assistive listening and alerting devices, such as telephone amplifiers. If you have trouble hearing, visit your doctor or hearing health care professional to find out if you have a hearing loss and, if so, how to treat it.

The Food and Drug Administration regulates hearing aids and other devices used to prevent, diagnose, and treat hearing loss to ensure that they are safe and effective. But the agency also hopes people will help themselves by protecting and caring for their ears.

From Sound Waves to Brain Waves

To better understand hearing loss, it helps to know how people hear the sounds around them. According to the NIDCD, people don't just hear through their ears — they hear with their brains. A vibration, which can be transformed into the sound of a moderate rain, a rock lyric, or the blast of a chainsaw, is first picked up by the ears and then "read" by the brain.

The ear is made up of three parts: the outer ear (pinna or auricle), the middle ear, which includes the eardrum (tympanic membrane), and the inner ear (cochlea), which is shaped like a snail shell and lined with tiny hairs.

Hearing loss occurs when the tiny hairs inside the cochlea are damaged or die, a common occurrence as people age. Hair cells, which pick up sound waves and transform them into nerve impulses, do not regenerate. That's why most hearing loss is irreversible.

Sound enters the outer ear and strikes the eardrum, causing it to vibrate. The eardrum's vibrations are amplified through the chamber of the middle ear along three tiny interconnected bones, named for their shapes — hammer (malleus), anvil (incus), and stirrup (stapes) — which pass on the vibrations of sound waves to the cochlea.

The brain interprets the nerve impulses from the cochlea as the ring of a doorbell or telephone, words being spoken, or the honk of a car horn. The combination of pitches, or frequencies, give different sounds their distinctive qualities. The brain also uses the source and direction of the sound and loudness as clues to decipher messages.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.