A Cochlear Implant is a device that can be surgically implanted into a person's cochlea to stimulate it to cause hearing. It consists of a tiny receiver which is placed under the skin in the bony part behind the ear. The receiver has a probe with several electrodes (usually 22 now), that is implanted into the cochlea. A cochlear implant can be useful if the hearing loss is caused by problems with the cochlea (usually damaged hair cells) or where the loss is caused by problems with the middle ear that cannot be corrected.
A person with a cochlear implant also wears a hearing aid like device that has a microphone, a processor and a transducer. The processor manipulates what the microphone hears and sends a signal to the transducer, which is usually worn just behind the ear. The transducer changes the signal from an electrical signal to a magnetic signal that can be received through the skin by the implanted receiver. The receiver then stimulates the probe in the cochlea causing the person to hear.
Cochlear implants are relatively new and they are still only used in cases of profound hearing loss.
Not all cochlear implants are successful; some types of hearing loss are not improvable with a cochlear implant and some are only partially successful. But, many people with cochlear implants can understand spoken words without being able to see the speakers lips and even understand words spoken over the phone.
There is considerable controversy over cochlear implants. Some people, especially
some Deaf people, feel that cochlear implants are experimental and may not
be best for children, who could lead perfectly fulfilling lives as Deaf individuals
without assuming the medical and psychological risks of an implant. They fear
that hearing parents (about 90% of all Deaf children are born to hearing parents)
may be subjecting their children to unnecessary risks in order to make the
child hear "like them".