Today I opened the blog of someone who commented they hated Cochlear Implants. This person indicated there were hearing aids and that should be good enough for anyone. As a post-lingually deafened adult who has a highly successful Cochlear Implant I find it fairly frustrating with the amount of mis-information around about what a Cochlear Implant is and does and who should have one.

Firstly, a Cochlear Implant is not an alternative to wearing a hearing aid. A cochlear implant is only an option if a person cannot effectively use hearing aids. A Cochlear Implant is not a high powered hearing aid and does not amplify sound as a hearing aid does. It is a serious decision to have an implant and one which is only taken after much testing for suitability and all other avenues for hearing are explored.

The type of hearing loss an implant works best for is sensorineural deafness, a common cause of hearing loss which is often age related, where the hair cells in the cochlea have died or are damaged. These hair cells translate sound vibrations, received from the eardrum through the middle ear, into an electrical impulse and send the impulse to the hearing nerve. The hearing nerve takes the electrical impulse to the brain and we hear sound.

If someone’s hair cells in their cochlea have died or are damaged then the connection is missing. It doesn’t matter how loud the sound, it cannot be heard. Let’s say you have the latest technology stereo system and great surround sound speakers. If you don’t connect the speakers to the system you will not hear sound. In sensorineural deafness the connection is missing and a cochlear implant provides this connection.

A cochlear implant consists of two parts. The first part is the internal implant which is inserted under surgery. It is routine surgery, generally 2-3 hours, with only a small incision. The internal implant is basically a radio transmitter sitting on the skull with electrodes which are inserted into the cochlea. The external speech processor, while it looks a bit like a hearing aid is actually four small computers which, through microphones, receive sounds and translate them to electrical impulses. These electrical impulses are transmitted to the internal implant radio transmitter which sends them to the electrodes in the cochlea. The electrodes are the connectors and take the place of those missing hair cells stimulating the hearing nerve with electrical impulses. The impulse travels along the hearing nerve to the brain where sound is interpreted.

This electrical impulse received in the brain is much the same as anyone with normal hearing experiences through the natural process in the cochlea. This means the sound a cochlear implantee gets is usually very close to the sound they used to hear. One implantee told me how a few weeks after her processor activation she took a phone call and was able to identify the speaker. She hadn’t spoken by phone to that person for more than 20 years and had only seen them a few times as well. So if she could identify someone over the phone having not heard them speak for many, many years, then the sound she was hearing had to be very similar to what she heard before.

Having a cochlear implant is a big decision. For some it is the only way they can hear.

Professor Graeme Clark the inventor of the Cochlear Implant was this year’s Boyer lecturer for ABC radio in Australia. He talks about how devastating it is to lose a major sense – not just hearing but any sense. He discusses how the technology used for the Cochlear implant is now being researched for new uses, such as paraplegia and blindness. The transcript of his lectures can be found at http://www.abc.net.au/rn/boyerlectures/stories/2007/2084224.htm

For stories of people who have regained their hearing log on to http://www.c-a-network.com. For more information about Cochlear implants http://www.cochlear.com