History of the Cochlear Implant

If you have seen a cochlear implant, you may wonder how such a device came to be. The history and development of the cochlear implant, a modern tool for hearing, actually spans centuries.

Pre-Modern Times

Around 1790, a researcher named Alessandro Volta placed metal rods in his own ears and connected them to a 50-volt circuit. This is the first known attempt at using electricity to hear.

Later around 1855, another attempt was made to stimulate the ear electronically. There were also other experiments in using electrical treatment for ear problems.

Silver Age

In the Depression years of the thirties, researchers found that putting a current near the ear can create auditory sensations. The scientific community also learned more about how the cochlea works. An important advance was made when researchers discovered that electrical energy can be transformed into sound before reaching the inner ear.

The year 1957 brought the first stimulation of an acoustic nerve with an electrode, by the scientists Djourno and Eyries. In that experiment, the person whose nerve was being stimulated could hear background noise.

Research really accelerated in the sixties. There was continued research into the electrical stimulation of the acoustic nerve. A major advance was made when researchers learned that specific auditory nerves must be stimulated with electrodes in the cochlea in order to reproduce sound. Dr. William House implanted three patients in 1961. All three found they could get some benefit from these implants. A few years later, from 1964 to 1966, an array of electrodes were placed in cochleas, with satisfactory results. Researchers learned even more about the positioning of electrodes and the results of that positioning.

Modern Times

Implant technology leaped forward in the seventies through the nineties. The seventies saw more people getting implanted, continued research, and the development of a multichannel device.

In 1984, the cochlear implant was no longer deemed experimental and was given the stamp of FDA approval for implantation in adults.

Throughout the nineties, other improvements were made in speech processors and other implant technology, particularly the miniaturization of the speech processor so that it could be incorporated into a BTE hearing aid-like device.