How does a Cochlear Implant Work?

Michael Anissimov
Michael Anissimov

A cochlear implant is a device that allows the deaf or extremely hard of hearing to hear again. About 100,000 people worldwide have these implants. A cochlear implant works by bypassing the eardrum and directly stimulating the cochlea, the spiral-shaped structure in our inner ear responsible for detecting sound.

A cochlear implant allows deaf or hard of hearing patients to hear sound again.
A cochlear implant allows deaf or hard of hearing patients to hear sound again.

A small microphone implanted just above the ear connects to a speech processor, which filters speech from surrounding noise, which uses electromagnetic induction — the same phenomenon exploited by metal detectors and RFID tags — to send a signal to a receiver and stimulator located in the inner ear, which sends auditory signals directly to the brain.

With a cochlear implant, a person's eardrum is bypassed and the cochlea is directly stimulated.
With a cochlear implant, a person's eardrum is bypassed and the cochlea is directly stimulated.

The total cost of a cochlear implant, including surgery and post-implantation therapy, runs between $45,000 and $55,000 US Dollars (USD), but can be as high as $80,000 USD for adults born deaf who require additional therapy to learn to process sounds. About 3,000 people have bilateral implants, that is, one in each ear, and this trend is growing, with about 15% of cochlear implantees in the United States choosing this option today. Cochlear implants were invented back in the 1970s.

Cochlear implants may come with different types of software for the speech processing module, which emphasize different parts of sound. This software is continuously improving and in many cases new versions can be added in to preexisting patients without the need for additional surgery. Cochlear implants are most successful with children, who, even if born deaf, have the necessary neural plasticity to pick up the faculty of hearing with the least training. The longer you have been deaf, the more intensive the post-surgery training needs to be. Because the implantation of a cochlear implant destroys prior hearing capabilities in the ear in which it is implanted, this therapy is only recommended for those who are already entirely deaf or near-deaf.

Cochlear implants have sparked intense ethical debates among the medical and deaf communities. Some deaf people feel that cochlear implants unnecessarily alienate deaf people from the deaf community, particularly in situations where deafness runs in the family. But children receiving the implants give overwhelmingly positive feedback, and rarely if ever regret their parents' decision to go forward with the implant.

Michael Anissimov
Michael Anissimov

Michael is a longtime wiseGEEK contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

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Discussion Comments

anon1002973

You know, I understand where the deaf community is coming from when that fear that their culture is at risk of disappearing. I have the implant and grew up with very limited hearing before I went completely deaf. I knew what I was missing when I whet deaf therefore I could not wait to have the implant which in fact gave me more than I had before. We make efforts to learn the language of other countries so that we can immerse ourselves in their culture, that pretty normal, therefore, the deaf community encourages people to learn to sign.

pleonasm

My sister is an audiologist and she loves working with people who have just put in cochlear implants.

When she describes them it makes me think of the book "Extremely Loud and Incredibly Close". The title refers to a moment when a person who had not used their hearing implant for 20 years turns it on and for a moment there is only silence. Then a flock of pigeons flies past the window, extremely loud, and incredibly close.

I think that is just beautiful and the image has stuck with me. The idea of hearing something after such a long time of hearing nothing is wonderful.

croydon

I've heard a bit about the debate on whether or not people should be given the cochlear ear implant. It's a tough one to come down on.

Deaf culture is a real thing, although most people don't realize it. Since sign language is not widely spoken by non-deaf people, and a lot of deaf people don't learn how to read lips (which is very difficult) they really have an enforced isolation, particularly when they are children and can't relate to others over the internet.

If your child can hear and no one else in the family can, that child could indeed end up feeling left out.

On the other hand I think the fact that non-deaf children still have the option of learning sign language should also be taken into account when thinking about the cochlear implant controversy.

anon153072

I'm zach and i have a cochlear implant, and it seems all right! but it crackles too much.

anon33728

the first cochlear implant was by Charles Eyriès & André Djourno, in 1957. this was followed by house in 1961, who implanted 6 patients.

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