If you're very hard of hearing or deaf, a cochlear implant may help you get back a sense of sound. A cochlear implant isn't a hearing aid, which makes sounds louder. A cochlear implant is a small device that is placed in your ear through surgery. It works by sending impulses directly to your auditory nerve, which carries signals to your brain.
Although a cochlear implant doesn't make you hear normally again, it can help you with sounds. Most people with severe to profound hearing loss are able to understand speech in person or over the phone better than they did with a hearing aid. It can usually help you understand sounds around you, including telephones, doorbells, and alarms. Many people are also able to understand speech in noisy environments better than they did with hearing aids, and in some cases are even able to enjoy music again.
How does a cochlear implant work?
Cochlear implants are designed for children and adults with sensorineural hearing loss. This type of hearing loss typically involves damage to tiny hair cells in the cochlea. As a result, sound can't reach the auditory nerve, which usually receives information from hair cells. A cochlear implant skips the damaged hair cells to stimulate the auditory nerve directly.
What happens, exactly? If you get a cochlear implant, it will consist of parts that are placed through surgery under your skin, as well as parts that you wear on your body, like a hearing aid. The external part with attached head coil (audio or speech processor) is slightly larger than a normal behind-the-ear hearing aid. They work together to create a sensation of sound.
First, a surgeon places a receiver under your skin behind your ear, through a small cut. The receiver is connected to electrodes, which are surgically inserted into the cochlea. The surgery takes one to two hours to perform and is usually done as an outpatient so you don't have to spend the night.
One to two weeks after surgery, your doctor will fit you with three parts: a speech processor, a battery pack, and a transmitter. You wear the microphone, which looks like a hearing aid, behind your ear. The processor may be connected to the microphone and worn at your ear, or it may be worn somewhere else on your body, depending on your activity level, age, or lifestyle. These processors offer different program and telephone options, and the ability to connect to assistive listening devices and other listening devices, like an iPod. Some have rechargeable batteries to lower costs.
When there are sounds around you, the microphone and processor pick them up and change them into electrical impulses. Then the transmitter sends these coded signals to the receiver under your skin. Next, the receiver delivers the signals to the electrodes inserted into the cochlea. These electrodes stimulate the auditory nerve, which carries the signals to the brain, where they are recognized as sound.