Q. I think I need a hearing aid. Any recommendations?

(I've received this question from more than a few readers. It's a subject of great interest to seniors, so I'm going to write two columns on hearing aids.)

About one in three Americans over 60 suffers from loss of hearing, which can range from the inability to hear certain voices to deafness. However, only about one out of five people who would benefit from a hearing aid uses one.

It's important to explain that a hearing aid will not restore your normal hearing. With practice, however, a hearing aid will increase your awareness of sounds and what made them.

If you think you have a hearing problem, get checked by your personal doctor. If your hearing is diminished, the doctor will probably refer you to an otolaryngologist or audiologist.

An otolaryngologist is a physician who specializes in treating the ear, nose, and throat. An audiologist is a health professional who conducts hearing tests to define your loss. Many otolaryngologists have audiologist associates in their offices.

Presbycusis, one form of hearing loss, occurs with age. Presbycusis can be caused by changes in the inner ear, auditory nerve, middle ear, or outer ear. Some of its causes are aging, loud noise, heredity, head injury, infection, illness, certain prescription drugs, and circulation problems such as high blood pressure. It seems to be inherited.

Tinnitus, also common in older people, is the ringing, hissing, or roaring sound in the ears frequently caused by exposure to loud noise or certain medicines. Tinnitus is a symptom that can come with any type of hearing loss.

Hearing loss can by caused by "ototoxic" medicines that damage the inner ear. Some antibiotics are ototoxic. Aspirin can cause temporary problems. If you're having a hearing problem, ask your doctor about any medications you're taking.

Hearing aids have a microphone, amplifier, and speaker. Sound is received by the microphone, which converts the sound waves to electrical signals and sends them to an amplifier. The amplifier boosts the signals and then sends them to the ear through a speaker.

Hearing aids are primarily useful to people who have suffered sensorineural hearing loss from damage to the small sensory cells in the inner ear known as hair cells. The damage can be caused by disease, aging, or injury from noise or drugs.

A hearing aid magnifies sound vibrations. Surviving hair cells detect the larger vibrations and convert them into signals that are sent to the brain.

There are limits to the amplification a hearing aid can provide. In addition, if the inner ear is too damaged, even large vibrations will not be converted into signals to the brain.

(In the next column, we'll discuss getting a hearing aid.)

