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HEARING AIDS AND COCHLEAR IMPLANTS
Hearing aids and cochlear implants work in slightly different manners to facilitate sound transmission for individuals with hearing loss. Generally speaking, hearing aids work much like "public address" systems. Each hearing aid, which is run by batteries, contains a microphone (picks up sound around you), an amplifier (makes the sound louder), and a receiver (delivers the sound to your ear). There are three basic types of hearing aids. Custom In-the-Ear Hearing Aids (ITE) have small components that fit in the bowl of the ear which are intended for mild to moderate hearing loss. Behind-the-Ear Hearing Aids (BTE) sit behind the ear and are coupled to an ear mold which fits into the ear. These aids have the flexibility to fit every type of hearing loss.
Pocket (Body) Hearing Aids are carried in a pocket or worn on the body. This type of aid is intended for severe to profound hearing losses.
Cochlear implants are surgically implanted devices that send sound information via electrical stimulation directly to the auditory nerve, bypassing the damaged, missing or non-functioning sensory receptors (hair cells) located within the inner ear. These are unlike hearing aids which simply amplify sounds and send the signals to these sensory receptors. In order to have access to environmental sounds and speech information, a person with a cochlear implant must wear an external sound processor (either a body-worn, pager-sized model or a behind-the-ear model) and a microphone. Sound is picked up at the level of the microphone and sent to the sound processor where the sound signals are converted into digital signals. These digitized signals are then delivered to an internal electrode array that was surgically placed in the inner ear. Contacts on this electrode array electrically stimulate hearing nerve fibers which, in turn, carry the signals to the brain where they are "heard."
Cochlear implants have received Food and Drug Administration approval for use in adults with severe or profound hearing loss in both ears who receive little or no benefit from the use of hearing aids. They are also approved for children 12 months of age or older who have profound hearing loss in both ears, and who receive little or no benefit from hearing aids. The type of amplification device that is best for an individual must be determined by a thorough examination by an audiologist.