Cochlear implants
How the ear works
The auditory system is made up of the outer, middle and inner ear.
The outer ear funnels sound down the ear canal to the eardrum, which protects the middle ear.
The eardrum transforms sound into vibrations, which are transmitted to the “bones of hearing” -- the hammer (malleus), the anvil (incus), and the stirrup (staples). These bones are constantly moving, and they change sound from mechanical to hydraulic information suitable for passing through the fluid-filled cochlea in the inner ear.
Within the inner ear, tiny hairs in the cochlea stimulate the nerves of hearing, which carry sound to the brain for processing.
What is a cochlear implant?
A cochlear implant is an electronic device that helps provide the sense of sound. Rather than amplifying sound as a hearing aid does, a cochlear implant translates sound into electrical impulses and sends them to the auditory nerve.
While hearing aids work well for those with mild to moderate hearing loss, cochlear implants work best for people who are severely deaf, especially those in whom the cochlea has been damaged.
The cochlear implant consists of:
- A microphone and speech processor/transmitter, which sits sit behind the ear. It looks similar to a behind-the-ear hearing aid. The microphone picks up sound, the speech processor selects and arranges it, and the transmitter sends the signal.
- A receiver, which is implanted in the skin just behind the ear. It receives the electrical signals and sends them through a wire that’s threaded into the inner ear to electrical connections on the cochlea. This bypasses the damaged inner ear. The signals then enter the auditory system and go to the brain.
Who can get a cochlear implant?
Those whom hearing aids will not help are the best candidates. Anyone from an infant to an adult can receive and benefit from a cochlear implant.
What is involved in receiving a cochlear implant?
A candidate for a cochlear implant is commonly evaluated by a physician and an audiologist. After being tested and evaluated, a surgical procedure installs the internal parts of the implants. A month to a month and a half later, the external parts are added and programmed.
Repeated follow-up visits might be necessary for an audiologist to complete the mapping of the device, making adjustments to the speech processor as necessary to help improve hearing
Learning to use a cochlear implant
The person who receives a cochlear implant is not having the sense of hearing “cured” -- it will not be like normal hearing. Instead, the implant provides the perception or representation of sound in an environment. It takes time to learn or relearn how to hear.
Extensive therapy might be involved to help the person who has received the implant learn to communicate effectively.
