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A guide to cochlear implants
This small, complex system stands in for ear parts that don't work.
Cochlear implants are surgically implanted, electronic devices that help correct severe hearing problems in children and adults.
Cochlear implants aren't for everyone. They require the time, health and commitment to undergo testing, surgery, healing and extensive training. Depending on when people lost their hearing, implants may be more or less likely to help.
The best candidates for implants include adults who have lost all or most of their hearing late in life and children as young as 12 months old.
Anatomy of an implant
Cochlear implants have four main parts, according to the National Institute on Deafness and Other Communication Disorders (NIDCD): a microphone, a speech processor, a receiver/transmitter and an electrode array.
The microphone, worn just outside the ear, picks up sounds. These sounds are sent down a wire to the speech processor, a small computer that may be placed in a pocket, on a belt, or behind the ear, depending on its size. The processor selects and arranges the sounds from the microphone and converts them into electrical signals.
The processor sends these signals through another wire to the transmitter, which sits behind the ear, up against the scalp. The transmitter sends the signals through the skin to a receiver that has been surgically implanted under the scalp. The receiver sends the signals to electrodes in the inner ear.
From the inner ear, the signals travel up the auditory nerve to the brain, which interprets the signals as sounds.
The implant process
Anyone considering an implant should talk to a few medical specialists and an experienced surgeon, says the NIDCD.
People who decide on an implant will have tests, such as x-rays, and other medical evaluations to determine the cause and degree of their hearing loss.
The surgery usually requires general anesthesia, which makes the person unconscious during the surgery. It takes three to five hours to place the electrodes and receiver. The surgeon will cut the skin behind the ear and drill a hole in the bone, then thread the electrodes into the inner ear. The receiver is placed in the bone, and the cut is stitched shut.
After two to four weeks of healing, the microphone, processor and transmitter are connected to the system. The processor is programmed by testing the effect of each separate electrode.
Once the system is programmed and in place, the person can start learning how to interpret the sounds created by the implant. This often includes the help of a speech-language pathologist and an audiologist.