What is a Cochlear Implant?

Some of you have asked for more information on what a cochlear implant is, I probably should have started with this post so you all knew what I was referring to this whole time :). First, I will explain how a person hears normally (refer to labeled ear diagram above, you can click on any picture to enlarge it):

• Sound waves enter the ear canal and travel to the eardrum
• The sound waves cause the eardrum to vibrate, then it sends the three smallest bones in the body (Hammer, Anvil, Stirrip) into motion
• The motion is converted into electric impulses by the tiny hair cells (thousands) found in the cochlea
• The electric impulses are sent to the hearing nerve to the brain, where they are perceived as sound for the listener
  

For my ears, everything is working except for the hair cells within the cochlea. I have a sensorineural hearing loss which means the source of my hearing loss is within the inner ear (cochlea). I have abnormal hair cells, they are weak or not there at all. Most definitely the case for my high frequency sounds which I have always had difficulty hearing.

A cochlear implant is a surgically implanted electronic device that gives a person with a hearing loss a sense of sound (see implant above). The individual has to be profoundly deaf or severely hard of hearing. Where hearing aids only amplify sounds, cochlear implants directly stimulate any functioning auditory nerves with electrical impulses within the cochlea. My audiologist Claudia, explained it the best for me...cochlear implants are to contact lenses as hearing aids are to glasses. It goes directly to the source of sound or sight.

How a cochlear implant works (see numbered ear diagram above):

1. Sounds are captured by the sound processor (see above) which is worn on the outside of the body. It looks like a hearing aid with a magnet attached to connect to the internal implant. (So, if I were to get too close to a refrigerator, my implant could go flying on the fridge :), this has happened to my brother a couple of times, I will train myself to not get too close to a fridge, ha).

2. The sound processor synthesizes the sounds into digital information then sent to the internal implant through the magnet.

3. The internal implant changes the digital information into electrical signals. Then, they are sent to the electrode (looks like a wire, see photo above) that is inside of the cochlea.

4. Signals from the electrode bypass the damaged hair cells to stimulate the hearing nerve, which allows the brain to receive sound.

That's it, that is how I will be able to hear! Simple enough huh? Ha, yeah right! I will be implanted with the Nucleus Freedom by Cochlear (www.cochlear.com).

If you want more specific information, the following websites are helpful:

www.nidcd.nih.gov/health/hearing/coch.asp
www.fda.gov/cdrh/cochlear/index.html