Professor Graeme Clark pioneered the Multi-channel Cochlear Implant for severe-to profound deafness: the first clinically successful sensory interface between the world and human consciousness, and the first major advance in helping deaf children and adults to communicate in a world of sound.
The multi-channel cochlear implant (bionic ear), pioneered by Professor Graeme Clark at the University of Melbourne, is the first cochlear implant to reliably give speech understanding to severely and profoundly deaf people, as well as spoken language to children born deaf. It is considered by educators and clinicians to be the most important advance in the history of the management of profound deafness. By providing speech understanding it is also the first and only effective sensory interface with the brain. It has been developed industrially by the company Cochlear Limited, which has had the major share of the world markets for the last 25 years, in part due to the ongoing research led by Professor Clark. By the end of 2011 the Cochlear device has been implanted in more than 150,000 people in over 100 countries.
When Clark started his research in 1967 he did so against considerable opposition from the scientific and medical community. In the 1960s the general scientific view, as expressed by the US hearing physiologist Merle Lawrence was that “Direct simulation of the auditory nerve fibres with resultant perception of speech was not feasible”. This meant that Clark had very little funding for his initial, crucial research. Nevertheless he was able to demonstrate that, although electrical stimulation created an information “bottle-neck” between sound and the central brain pathways, some speech information could be transmitted by both rate and place of stimulation in the brain. But the big question was: what speech information could be transmitted through the bottle neck to provide speech understanding. This seminal question could only be answered by testing with deaf people, and not by experimental studies on animals. Clark, also as a surgeon, opted correctly to develop a multi-channel device that was fully implantable with information and power transmitted through the intact skin, rather than run the risk of introducing infection through the skin using a plug and socket. This was to be a very expensive exercise that Clark was fortunately able to fund through the generosity of a television proprietor running public telethons.
Before operating on people there were many difficulties to resolve. His specialist ear surgeon colleagues considered that the inner ear should not be operated on - the very nerves that were to be stimulated could be destroyed. Middle ear infections, especially common in children, could spread to the inner ear and lead to meningitis. Furthermore, the electrode bundles would not pass around the tightening spiral of the inner ear to the speech region until Clark discovered in a shell (a replica of the cochlea) that it needed to be flexible at the tip and progressively stiffer towards the base.
Clark the surgeon operated on the first patients, as he was head of the clinic and felt it was his responsibility to lead in this way. Then after the patients recovered, Clark, who had also trained as an auditory neurophysiologist, led the research to see what the electrical stimuli sounded like, and find a coding strategy that could be understood as speech. He had also trained in speech science to assist in this challenge.
Then in 1978 Clark and his small team made the major break through and the first patient heard speech. It was the very first time that anyone had shown that an artificial sensory stimulus could be interfaced to human consciousness.
Having taken it thus far, Clark then turned around and became the driving force in seeking government funding for its industrial development. He then worked closely with industry to ensure that it became viable. He also had a longer term view and led further research to make the improvements that would ensure that it remained the market leader internationally to this day. To assist he organized three world congresses, spoke at many international meetings and arranged workshops to train others in the use of the implant.
Then Professor Clark embarked in search of his ultimate dream and that was to see if children who were born deaf could develop spoken language. Again Clark did this in the same methodical, scientific and ethical way he had approached all aspects of this research. He again led as the surgeon taking full responsibility if any mishaps occurred. He was head of the clinic and supervised all the clinical studies As physiologist, psychophysicist and speech scientist he led the fundamental research to see how best to achieve speech understanding for children. In addition as ear biologist and pathologist he ensured that operations on young children would be as free as possible from any adverse effects, including the risk of meningitis following a middle ear infection - common in the young.
In 1990 the US Food and Drug Administration approved the implant as safe and effective for children from two and above. This established the implant as the first in the world to receive regulatory approval for regular clinical use in children.
Since that time Professor Clark has continued to push back the boundaries for the multi-channel cochlear implant and aims to achieve high fidelity sound using nanobiotechnology. In addition he has been helping to establish a whole new field of medical research he has referred to a Medical Bionics. These new goals are being pursued through the creation of the Graeme Clark Foundation, and his appointment as Distinguished Researcher at ICT for Life Sciences located in Electrical and Electronic Engineering at The University of Melbourne.
- A partnership in Research Leading the Bionic Ear and Beyond 2008: The ICT Life Sciences Graeme Clark Oration 2008, Melbourne, Australia
- The cochlear implant: a model for bio-medical innovation and industrial development, Australian Research Council's Graeme Clark Research Outcomes Forum 2008, Canberra, Australia
- The multiple – channel cochlear implant: The sensory interface between the world of sound and human consciousness. Graeme Clark, A principal speaker, Frontiers in Medicine at Nobel Forum: Cochlear Implants from Bench to Bedside, Karolinska Institutet
- Speech understanding with the multiple – channel cochlear implant: interfacing electronic technology to human consciousness. Plenary address, Interspeech 2005 – Eurospeech conference, Lisbon
- What can electrical stimulation with a cochlear implant tell us about brain function and human consciousness and how can it alleviate severe sensory neural deafness? Nobel Forum at the Karolinska Institutet in Stockholm
- In search of the ideal connection between sound and the brain for cochlear implants - Nobel Forum at the Karolinska Institutet in Stockholm
- Otto Schmitt Lecture, The International Federation of Medical and Biological Engineering
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