Cochlear Implant

Cochlear implants are surgically implanted devices that replace the function of the inner ear, or cochlea, for people with severe to profound hearing loss.   Cochlear implants do not restore normal hearing but they do give people more awareness of sounds.  Unlike hearing aids, which amplify sounds, a cochlear implant bypasses damaged portions of the inner ear to deliver sound signals electronically to the hearing (auditory) nerve.   These signals stimulate the auditory nerve, which then directs the signal to the brain. The brain interprets those signals as sounds, although these sounds aren’t like normal hearing because they are electrical stimulation. It takes practice and persistence to learn to interpret the signals received from a cochlear implant. Within six months of use, most people with cochlear implants have made good progress in understanding speech and are following conversation better than with their hearing aids.

A special sound processor is worn behind the ear or against the head above the ear. The microphones on the processor pick up sounds and convert them into electrical impulses which are sent to the internal electrode device in the inner ear. Imagine a piano keyboard, which goes from low pitches like a fog horn on the left side of the keyboard to the high pitches like a bird whistle on the right side of the keyboard. The cochlea is just like this, except the high pitches are represented at the exterior of the snail shape and the low pitches are represented at the interior of the snail shape. The implanted electrode curls around the snail shape of the cochlea and stimulates the different areas of the inner ear that represent low, middle and high pitched sounds. Hearing goes from acoustic (sound waves in the air) picked up by the outside processor to electrical stimulation through the electrode. Sound from cochlear implants is very different from hearing aids, and sometimes is described as electrical beeps or robotic speech. Over time the brain learns to recognize these sounds and they become more natural.

When even the best-fit hearing aids are not enough to follow conversations, or hear on the phone, cochlear implants can help people with severe to profound hearing loss better understand the sounds and conversations around them.

Individuals aged birth to 100+ are able to be considered for cochlear implant candidacy.  Babies and children benefit by having full access to sounds around them so that they can develop speech and language skills.

Often people who have worn hearing aids for many years find that they are having greater difficulty hearing, especially in groups or background noise. When hearing levels reach the severe hearing loss range, and speech clarity is reduced, a cochlear implant may be recommended.

Audiologists perform special hearing tests to see if a person is a candidate for cochlear implants. Testing goes beyond the standard audiogram and speech understanding tests to include  testing with hearing aids and testing words and sentences in noise.

The cochlear implant is turned on anywhere from 3-4 weeks after the surgery to allow the ear to heal.  The audiologist will test the device to be sure the internal parts are working and program the sound settings to get the person started.

For babies and young children the audiologist will work closely with the parents, educational specialists and a speech-language pathologist. The team works together to support the child’s adjustment to the device and to be sure the child is getting the most out of it. Often early intervention services come to the home to help the parents provide extra stimulation and enrichment activities to help with listening, speech and language development.

For adults, sound will be very different from what they may have heard with hearing aids.  The brain needs time and lots of practice to identify the new sounds.  Just like people have physical therapy and home exercises after a knee replacement, adults  need several appointments with the audiologist for adjustments as their brain gets used to the new sounds and a plan for listening therapy and home practice.  People who are really motivated to practice and wear the implants full time, all of their waking hours, will have the best outcomes. Some people are even able to have a phone conversation with a familiar person, something they could never have done with their hearing aid.  Most people report that after the first year they notice big improvements in their ability to follow conversation and improved quality of life.