Dalhousie University

Cochlear Implant Program


Professor Graeme Clark of the University of Melbourne was the son of a deaf father. He worked diligently to develop a bionic ear to rehabilitate deafness and hearing loss. This bionic ear is called a cochlear implant.

In 1967 at the University of Sydney, Clark began his research. Then, in 1968 Clark began working and continued researching at the University of Melbourne. By 1978, he had performed the first successful cochlear implant operation. With the success of this operation, a medical equipment manufacturer, Nucleus, became interested in cochlear implants.

In 1981, Nucleus, with approval from the University of Melbourne and the Australian Government, began worldwide clinical testing of cochlear implants.

The Maritimes began implantations in May, 2001. Dr. Manohar Bance performed the first surgery.

To understand how a cochlear implant works, a bit of background information is necessary. There are three sections to the ear: the outer ear, the middle ear, and the inner ear. Within the inner ear, there are tiny hair cells that help to process sound.

Sometimes, these hair cells are bent or broken, resulting in hearing loss. A cochlear implant will allow people with bent or broken hair cells to hear.

A cochlear implant is a coil inserted into the inner ear. On this coil are tiny electrodes. Also inserted into a person's skull is a tiny magnet. On the outside of the ear, connected by a magnet attracted to the internal magnet, a person wears a microphone and database pack.

The microphone picks up all sound that an ear without hearing impairments would pick up. Then, these sounds are sent to the database pack. Here, sound is processed and then sent to the electrodes on the coil as vibrations. These electrodes then stimulate a nerve connected to the brain; the vibrations are sent to the brain where they are processed as sound.

To be a successful candidate for a cochlear implant, the candidate must receive little or no benefit from the use of a conventional hearing aid. Also, the shorter the period between the onset of deafness and receiving an implant, the more the candidate will benefit from receiving a cochlear implant.

If the candidate is successful and receives a cochlear implant, results may vary. Most recipients, however, have results which include hearing medium level and soft sounds, being able to differentiate among environmental sounds, understanding speech over the telephone, positive effects on feelings of involvement in daily life, self-worth, and relationships with family, friends, and co-workers, and an improved ability to monitor the quality and volume of voice.



Dalhousie University Faculty of Medicine