What is a cochlear implant?
A cochlear implant is an electronic device that provides a sensation of hearing to individuals who are deaf. It does not provide "normal" hearing, but the device can allow children to detect and differentiate among sounds.
It consists of two main parts: an external part worn somewhat like a hearing aid, and an internal part which must be implanted by a surgeon.
The external part of a cochlear implant is the speech processor. It has a "microphone" worn over or behind the ear. The microphone feeds the sound to the speech processor in the form of electricity. The speech processor codes the sound input into electrical signals which are sent back through a cord to the ?transmitting coil,? a thin plastic piece about one inch in diameter containing a magnet placed on the side of the head behind and slightly above the ear.
The transmitter sends the signals across the skin to the internal part of the implant (the "receiver/stimulator"), which is under the skin.
The receiver/stimulator sends the signals into the electrode array, which is a one-inch long wire surgically inserted into the inner ear. The electrode array consists of several electrode bands, each of which can provide a tiny current to the inner ear, to replace the function of the damaged or missing hair cells of the cochlea which ordinarily would stimulate the nerve endings of the auditory nerve.
Implants from different manufacturers differ in the number of channels, programming strategy, and appearance of the externally worn device. Behind-the-ear processors are available to eliminate the need for a body pack for many cochlear implant users.
Does a cochlear implant provide normal hearing?
No. A cochlear implant provides a limited sense of hearing in the implanted ear. However, most individuals with good language abilities can learn to use this sound to understand spoken language. Many cochlear implant users can learn to understand spoken sentences without looking at the person who is talking, particularly if there is no background noise. Many can also learn to use the telephone.
Who can benefit from a cochlear implant?
Children who were born without hearing, and children who lose their hearing can benefit from an implant. Adults and children who once had enough hearing to perceive the sounds of speech have an easier time learning to use the new sound through an implant, but many children who never heard sounds before can learn to understand speech using the implant, if they have good cognitive (learning) abilities.
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