The encyclopedia · Product & Design · Product decision · 1978–1990
Cochlear's multi-channel implant coded speech into place for open-set hearing
Graeme Clark's 1978 speech-coding strategy mapped formants to electrode position; Cochlear Ltd turned it into a device the FDA approved from 1985.
Cochlear Limited
The solution
Hearing aids amplify sound, but people with severe-to-profound deafness have too little working hair-cell function to benefit. Early single-channel implants gave a crude sensation of sound but rarely intelligible speech.
At the University of Melbourne, Graeme Clark showed that frequency is coded by place along the cochlea and that stimulating multiple sites with a speech-coding strategy — second formant for place, voicing for rate, sound pressure for level — could transmit enough of speech through the neural bottleneck. His first strategy, from 1978, produced open-set speech understanding in standard audiological tests.
Cochlear Limited was founded in Australia in 1981 to industrialize the invention; the FDA approved the Nucleus Mini22 for adults in 1985 and for children in 1990. By 2008 the company had manufactured implants for roughly 90,000 recipients.
Why it worked
- Place coding uses the cochlea's own frequency map instead of fighting it.
- Extracting speech features fits more information through a narrow channel.
- A wearable speech processor made the implant usable outside the lab.
- Children implanted young develop spoken language far better.
What can be applied
When the damaged organ can't be repaired, don't amplify harder — build a new codec for the channel you do have: translate the signal into the dimensions the remaining biology can still carry.
Aftermath
The 22-electrode Nucleus became the global benchmark; the FDA's 1990 approval for children marked the first approval of a major advance for deaf children by a health regulator. Cochlear Limited grew into one of Australia's most successful medical-technology exporters, and multi-channel implants have since restored usable hearing to hundreds of thousands of people worldwide.
Sources
- The multi-channel cochlear implant and the relief of severe-to-profound deafness
- Necessity, the Mother of the Cochlear Implant Invention?
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