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History: Who developed the cochlear implant and why?
Volta's crazy experiments
Stimulating the auditory nerve
Cochlear - an Australian innovation success
Funding the project
The success continues
Cochlear - MAIN
Volta's crazy experiments

Interest in stimulating hearing with electricity began with Count Volta in the 18th century. Volta, an Italian physicist who developed the electric battery, connected batteries to two metal rods that he inserted in his ears. In 1800 he described that when the circuit was completed he received a 'jolt in the head' and then a sound 'a kind of crackling, jerking or bubbling as if some dough or thick stuff was boiling' (Epstein:1989: 34). Not surprisingly, Volta found that it was quite uncomfortable and did not repeat the experiment too often!

Fifty years after Volta, a Frenchman, Duchenne of Boulogne, tried using an alternating current to stimulate his hearing and heard what he described as a sound like an insect trapped between a glass pane and a curtain.

Alessandro Volta
Alessandro Volta

Stimulating the auditory nerve
The first direct stimulation of the auditory nerve in a human was performed during an operation by Lundberg in 1950 - the patient became aware of noise. In 1957, Djourno and Eyries implanted an electrode attached to an induction coil in the head of a deaf person. They were able to transmit a signal to the electrode via a radio antenna on the outside of the body. The person heard sounds resembling the chirping of a grasshopper or cricket. He was also able to recognise simple words like mama, papa, and allo. This experiment inspired many investigators about the possibilities of using implanted prostheses to enable deaf people to hear.

An important trial with multiple electrodes stimulating the cochlea was successfully performed by American surgeons, John M Doyle, William F House and an electronic engineer, James Doyle. In 1964 Dr F Blair Simmons et al (Stanford University Medical School) implanted six electrodes with success. The recipient could recognise simple tunes. This research increased the knowledge of how the brain coded frequencies and responded to electrical stimulation.

There was much more work done in the 1960s and 70s to increase knowledge of how the cochlea functions and how speech is perceived. Studies led to the idea that the best way for a profoundly deaf person to hear speech is by stimulating the auditory nerve using a multiple electrode device. Research in:

  • electrical and mechanical technologies
  • progress in materials technology and
  • experiments with pacemaker implants also increased the opportunities to advance with cochlear implants.

For more information on hearing experiments: http://www.medoto.unimelb.edu.au/info/history2.htm

Cochlear: an Australian innovation success
An Australian, Graeme Clark, was greatly inspired by Dr F Blair Simmon's work with multiple electrode implants. Graeme Clark's father was hearing impaired, he had sensori-neural deafness. His father was a pharmacist and often had to ask his customers to speak up about their medical problems, which embarrassed him and them.

In 1967 Clark embarked on a long journey towards fulfilling his dream of helping deaf people hear the spoken word again. As a PhD student at the University of Sydney, Graeme Clark reviewed the available research to 'investigate whether a single or multiple-channel (electrode) cochlear implant would be possible for the management of a profound hearing loss.' (Clark, 1969: 1)

He believed that implants on humans should not be done until basic research on animals had solved some of the problems. For ten years his research into electrical stimulation of the auditory nerve via an implant into the cochlea struggled along on animal experiments and university grant funding.

Graeme Clark
Graeme Clark
Courtesy: Department of Otolaryngology, The University of Melbourne.

Funding the project
In 1974 a telethon on Channel 10 in Melbourne generated enough funds to take his work to the prototype stage and in 1978 to test it in a human patient, Rod Saunders. The cochlear implant worked: Rod could perceive sound again.

This demonstration encouraged the federal government to finance commercialisation of the cochlear implant. The financing of the cochlear implant became a remarkably successful joint venture to manufacture and market the product. The three-way partnership was begun between researchers at the University of Melbourne, the Federal government and a medical equipment exporter called Nucleus. The researchers provided the scientific expertise, Nucleus contributed experience in making and selling advanced medical equipment and the government provided project management and over a million dollars in grants.

This partnership led to the formation of a string of Cochlear enterprises in the US, Japan and Switzerland including Cochlear Ltd in Australia.


(Cochlear Pty Ltd)
Cochlear enterprises around the world. (Cochlear Pty Ltd)
(Cochlear Pty Ltd)

Cochlear logo
(Cochlear Pty Ltd)


The Nucleus® 22 was introduced in 1983 and was the first use of a 22 channel implant. Since then the Australian cochlear implant system has been used by over 30 000 people in 50 countries. It is the world's most widely used cochlear implant system. By the early 1990s Cochlear Ltd was making a profit and Professor Clark was earning royalties.

The success continues
Features of the Nucleus® 22 Cochlear Implant System include:

  • Internal implant with 22 channels for more stimulation. More channels give more flexibility in programming, more pitch information and improved hearing in noisy situations.
  • SPEAK speech coding strategy, designed to improve speech comprehension, especially in noise.
  • A long history of speech processor upgrades including the Spectra, a lightweight, powerful body worn speech processor and ESPrit 22, a compact, ear level speech processor. (Cochlear, 2001)

In 1994, after five years of lobbying, the implant was approved by Japanese health insurance companies, opening up a market of up to 50 000 profoundly deaf people.

Nucleus® 24 Contour, introduced in 1999 uses a pre-curved electrode. The electrode is made with the curved shape of the cochlea, improving the sound quality and simplifying surgery. The design won the Australian Design Award™ of the Year 2000.

In Australia, Cochlear Ltd design in accordance with the Implantable devices standard and the European Cochlear implant standard.

Nucleus® 22
Nucleus® 22 (Cochlear Pty Ltd) Click image to view detailed pdf

Activity
Draw a timeline to summarise the history of cochlear implant technology, beginning with Volta's experiments
.

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