(This is the second of 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.

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.

It's important to understand 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.

The two primary types of electronics used in hearing aids are analog and digital.

Analog aids convert sound waves into electrical signals, which are amplified. Analog programmable hearing aids have more than one setting; the user can change the aid for listening in different environments.

Digital aids convert sound waves into numerical code before amplifying them. Because the code also includes information about a sound's pitch or loudness, the aid can be specially programmed to amplify some frequencies more than others.

These aids also can be programmed to focus on sounds coming from a specific direction.

Hearing aids vary in price according to style, electronic features, and local market conditions. Price can range from hundreds of dollars to more than $2,500 for a programmable, digital hearing aid.

There are many kinds of hearing aids.

Behind-the-ear hearing aids are made of a plastic case with electronic components worn behind the ear and connected to a plastic ear mold that fits inside the outer ear.

There are also open-fit behind-the-ear hearing aids. Small, open-fit aids fit behind the ear completely with only a narrow tube inserted into the ear canal, enabling the canal to remain open. Some prefer the open-fit hearing aid because their voices do not sound "plugged up."

In-the-ear hearing aids fit completely inside the outer ear. Some of these aids may have a small magnetic coil that allows users to receive sound through the circuitry of the hearing aid instead of a microphone. This feature helps with phone conversations.

Canal hearing aids fit into the ear canal and are available in two styles. The in-the-canal hearing aid is made to fit the size and shape of a person's ear canal. A completely-in-canal hearing aid is nearly hidden.

A middle ear implant is a small device attached to one of the bones of the middle ear. Rather than amplifying the sound traveling to the eardrum, a middle ear implant moves these bones. Both techniques improve sound vibrations entering the inner ear.

A bone-anchored hearing aid is a small device that attaches to the bone behind the ear. The device transmits sound vibrations directly to the inner ear through the skull, bypassing the middle ear.

The following are some important questions you should ask when getting a hearing aid:

Ÿ What features would be most useful to me?

Ÿ Is there a trial period to test the hearing aids?

Ÿ How long is the warranty? What does it cover?

Ÿ How long should I wear my hearing aid while adjusting to it?

Ÿ Please check to see if my hearing aid works with my cell phone.

The Times News, Inc., and affiliates (TIMES NEWS) do not endorse or recommend any medical products, processes, or services or provide medical advice. The views of the author do not necessarily state or reflect those of the TIMES NEWS. The article content is not intended as a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician, or other qualified health provider with any questions you may have regarding a medical condition.