Graeme Clark (doctor)

Graeme Milbourne Clark AC (born 16 August 1935 in Camden, New South Wales)[1] is an Australian doctor. He was a key figure in the research and development of the Bionic Ear – a multiple-channel cochlear implant.

Early life and education

Clark was born in Camden, New South Wales, and was educated at Scots College in Sydney. He studied medicine at Sydney University.[2][3]

He then specialised in ear, nose and throat surgery at the Royal National Throat, Nose and Ear Hospital and obtained a fellowship in 1964 from the Royal College of Surgeons, London. Clark then returned to Australia and became a Fellow of the Royal Australasian College of Surgeons and in 1969 completed his PhD at the University of Sydney on "Middle Ear & Neural Mechanisms in Hearing and in the Management of Deafness".[4][5] At the same time, he completed a Master of Surgery thesis on "The Principles of the Structural Support of the Nose and its Application to Nasal and Septal Surgery".

In 1976, he returned to England to study at the University of Keele, and to learn more about speech science, as this knowledge was also essential for enabling him to work on converting complicated speech signals into electrical stimulation of the hearing nerve.

Career

Development of cochlear implants

Clark hypothesised that hearing, particularly for speech, might be reproduced in people with deafness if the damaged or underdeveloped ear were bypassed, and the auditory nerve electrically stimulated to reproduce the coding of sound. His initial doctoral research at the University of Sydney investigated the effect of the rate of electrical simulation on single cells and groups of cells in the auditory brainstem response, the centre where frequency discrimination is first decoded.

Clark’s research demonstrated that an electrode bundle with 'graded stiffness' would pass without injury around the tightening spiral of the cochlea to the speech frequency region. Until this time he had difficulty identifying a way to place the electrode bundle in the cochlea without causing any damage. He achieved a breakthrough during a vacation at the beach; he conceptualised using a seashell to replicate the human cochlea, and grass blades (which were flexible at the tip and gradually increasing in stiffness) to represent electrodes.[6]

Clark showed that the electrode bundle had to be free-fitting, and the wires needed to be terminated with circumferential bands to reduce friction against the outer wall of the cochlea, and so make it easier to pass the required distance. The bands had to be wide enough to minimise the charge density of the electrical current for safety, but narrow enough for localised stimulation of the nerve fibers for the place coding of frequency. In order to address issues about the safety of the device, Clark conducted experiments to show that there was a minimal risk of meningitis from a middle ear infection if a fibrous tissue sheath grew around the electrode bundle. The sheath was developed from a connective tissue graft from the person’s own body that was placed around the electrode bundle where it entered the cochlea.

The ultimate question however was: could speech be coded with multi-channel stimulation so that it could be understood by a deaf person? This could only be discovered by operating on a deaf person.

The first multi-channel cochlear implant operation was done at the Royal Victorian Eye and Ear Hospital in 1978 by Clark and Dr Brian Pyman.[7] The first person to receive the implant was Rod Saunders who had lost his hearing aged 46.[3][8]

After successfully completing the surgery in 1978, with his post-doctoral colleague, Yit Chow Tong, Clark discovered how multi-channel electrical stimulation of the brain could reproduce frequency and intensity as pitch and loudness in severely-to-profoundly deaf adults who originally had hearing before going deaf. Electrical stimulation at low rates (50 pulses/sec) was perceived as a pitch of the same frequency, but at rates above 200 pulses/sec, what was heard was poorly discriminated and a much higher pitch. This discovery established that the timing of electrical stimuli was important for low pitch when this had been difficult to determine with sound. But discrimination of pitch up to 4000 Hz is required for speech understanding, so Clark emphasised early in the development of the cochlear implant that "place coding through multi-channel stimulation" would have to be used for the important mid-to-high speech frequencies. Clark and Tong next discovered that place of stimulation was experienced as timber, but without a strong pitch sensation. The patient could identify separate sensations according to the site of stimulation in the cochlea.

At the end of 1978, Clark and Tong made a ground-breaking discovery. This was the first speech processing strategy to give speech understanding to severely-to-profoundly deaf people using electrical stimulation alone, and in combination with lipreading. The speech processing strategy coded the second formant as place of stimulation along the cochlear array, the amplitude of the second formant as current level, and the voicing frequency as pulse rate across the formant channels.

Clark in December 1978 arranged that his audiologist present open-set words to his first patient, who was able to identify several correctly. Clark realized then that this was the breakthrough in providing speech understanding that everyone had been hoping for."it was the moment I had been waiting for. I went into the adjoining room and cried for joy."[9]

This discovery was established by Clark with objective audiological tests in 1979. The open-set speech test results on this patient were the first time that speech recognition for electrical stimulation alone had been demonstrated, under standardized conditions. Previously single-channel strategies had only shown a small improvement when electrical stimulation was used as a lip reading aid, but no speech understanding for electrical stimulation alone.

As a result Clark went on to operate on a second patient who had been deaf for 17 years. He was able to show that the speech coding strategy was not unique to one person’s brain response patterns, and that the memory for speech sounds could persist for many years after the person became deaf.

The successful development of the cochlear implant was confirmed when it gained approval from the Food and Drug Administration (FDA) in the United States. In 1982 Clark supervised the initial clinical studies mandated by the agency, and in 1985 after a world trial the FDA granted approval for the cochlear implant for adults 18 and over who had hearing before going deaf. It thus became the first multi-channel cochlear system to be approved as safe and effective by the FDA or any health regulatory body for giving speech understanding both with lip reading and for electrical stimulation alone in people who had hearing before going deaf. In 1990 after a detailed analysis of results the FDA announced that the 22-channel cochlear implant was safe and effective for deaf children from two to 17 years of age in understanding speech both with and without lip-reading[10]

In 1985, Clark as the surgeon-in-charge performed the cochlear implant surgery on the first children along with Drs Pyman and Webb. The first child was 10 years old and the second was 5 years old. From 1985 to 1990 Clark and the members of his Cochlear Implant Clinic at the Eye and Ear Hospital in Melbourne, followed by other clinics world wide, found that the formant extraction speech coding strategies developed by Clark and team resulted in up to 60% of children being able to understand significant numbers of words and sentences with electrical stimulation alone without help from lipreading. With a strategy that also extracted a band of high frequencies there were increased numbers of children with improved speech perception, speech production and language scores.

The Bionic Ear Institute

Main article: Bionics Institute

In 1970 Clark was appointed as the Foundation Professor of Otolaryngology (Ear, Nose, and Throat Surgery) at the University of Melbourne, and then in 2000 he was made one of the first Laureate Professors at the University for his international recognition of scientific achievement. He held this position till he retired in 2004. He led most of the pioneering cochlear implant research while Head of the Department of Otolaryngology. His research was funded initially by an appeal through a Telethon, and then a Public Interest Grant from the Australian government. His ongoing research to understand the functioning and improve the cochlear implant was through his grants from the National Health and Medical Research Council of Australia, the Australian Research Council, The US National Institutes of Health, and The Cooperative Research Centre program. In 1983 the Bionic Ear Institute was founded by Clark, as an independent, non-profit, medical research organization.[11] The goal of the Bionic Ear Institute was: "to give deaf children and adults the opportunity to participate as fully as possible in the hearing world and to find new ways to restore brain function". The Bionic Ear Institute renamed itself the Bionics Institute in 2011 due to an expansion of its aims not just to improve the bionic ear, but to develop a bionic eye and devices capable of deep brain stimulation.

Charity foundations

In 2002 The Graeme Clark Cochlear Scholarship Foundation was established in honor of Graeme Clark for his lifelong commitment to finding a solution for people with hearing loss, and his pioneering work in the field of cochlear implant technology.[12] Awarded by Cochlear Limited, scholarships are presented to cochlear implant recipients around the world to help defray the costs of their higher education consisting of financial assistance towards a college degree at an accredited university for up to four years).

In recognition of Clark’s contributions to the welfare of deaf people, The Graeme Clark Charitable Foundation, a charitable foundation has been established to firstly enable individuals with deafness and other sensory disorders develop their potential through appropriate biomedical, technological and educational measures. He also donated 2 million dollars to the deafness hearing charity which they greatly appreciated

Selected honours

Academic

Personal named distinctions

2002 The Graeme Clark Cochlear Scholarship, awarded annually, was established in Australia and the United States to assist people with cochlear implants to undertake tertiary studies.
2002 The Graeme Clark Room, the Ear Foundation, Nottingham, UK

Academic leadership

1984-2005 Founder and Director, The Bionic Ear Institute, East Melbourne, Australia
1970-2004 Foundation Professor of Otolaryngology and Chairman, Department of Otolaryngology, The University of Melbourne, Australia
1988-1996 Director, The Australian Research Council’s Special Research Centre the Human Communication Research Centre, East Melbourne, Australia

Selected bibliography

Books

Clark GM. (2003) Cochlear Implants: Fundamentals and Applications. Springer-Verlag, New York. (The first textbook on the cochlear implant, a major 800 page work written solely by Clark)
Clark GM. (2000) Sounds from Silence. Allen & Unwin, Sydney. (Clark’s Autobiography)
Clark GM. (1979) Science and God : Reconciling Science with The Christian Faith. Anzea Books, Sydney. ISBN 0-85892 097 2. ( Much is a vigorous debunk, by CLARK, of Evolution, esp. Chapter.3).

Patents

Hearing prosthesis - improvements in prosthesis

Inventors: G.M. Clark, J. Patrick, I. Forster, Y.C. Tong, R.C. Black. (1977)
Countries & Patent Nos.: Australia - 519,851 (3.11.77); Europe - 78.300567 (France, West Germany, The Netherlands, United Kingdom); Denmark - 78.4902; Japan - 1529582; U.S.A. - 4,267,410; Canada - 1,100,189.
(The first patent of a receiver-stimulator designed to stimulate the auditory nerve and for speech understanding)

Hearing prosthesis - speech processor

Inventors: G.M. Clark, J. Patrick, J. Millar, P.M. Seligman, Y.C. Tong (1979)
Countries & Patent Nos.: Australia - 535,489 (19.12.79); Europe - 80901001.0 (U.K, West Germany, France, Sweden, Italy, The Netherlands); Japan - Application No. 55-501189; U.S.A. - 4,441,202; Canada - 1,165,884.
(The first patent of the second formant/voicing speech hi processor for speech recognition in profoundly deaf people)

Improvements in speech processor, inventors

G.M. Clark, J. Patrick, J. Millar, P.M. Seligman, Y.C. Tong (1980)
Countries & Patent No.: Australia - 541,248; Canada - 391,699; Denmark - 549,881; Europe - 813,058,377; Japan - 19,874,081; U.S.A. - 4,515,158.
(The first patent for the second and first formant/voicing speech processor)

Improved sound processor for cochlear implants

DB Grayden, GM Clark (2006) (differential rate speech processor)
Countries & Patent No.: DE 60025735

Emphasis of short duration transient speech features, inventors

A Vandali and GM Clark (Transient Emphasis speech processor)
Countries & patent No: US 7444280, (28.10.2008)

See also

References

  1. ↑ The Graeme Clark Oration. About Graeme Clark page accessed 8 March 2014
  2. ↑ Suzannah Pearce, ed (2006-11-17). "CLARK Graeme Milbourne". Who's Who in Australia Live!. North Melbourne, Vic: Crown Content Pty Ltd.
  3. ↑ 3.0 3.1 "PROFESSOR GRAEME CLARK". Australian Broadcasting Corporation. 27 May 2004.
  4. ↑ "CLARK, GRAEME M". Faculty of Medicine Online Museum and Archive. Sydney Medical School.
  5. ↑ Herbert Voigt, Ratko MAGJAREVIC. Launching IFMBE into the 21st Century: 50 Years and Counting. Springer. p. 55.
  6. ↑ Rececca Scott (10 October 2013). "Inventor of Bionic Ear wins prestigious award and inspires new field of endeavour". The Age.
  7. ↑ G.M. Clark, B.C. Pyman, Q.R. Bailey,The surgery for multiple-electrode cochlear implantations, The Journal of Laryngology and Otology, Volume 93, Issue 03, pp. 215-223, year 1979.
  8. ↑ "About Graeme Clark". Graeme Clark Foundation.
  9. ↑ [Sounds from Silence Allen & Unwin, 2000], Sept 2008.
  10. ↑ Graeme M. Clark (24 August 2014). "The multi-channel cochlear implant: Multi-disciplinary development of electrical stimulation of the cochlea and the resulting clinical benefit". Hearing Research. doi:10.1016/j.heares.2014.08.002.
  11. ↑ "Bionic Ear Institute (1983 - 2011)". Encyclopedia of Australian Science.
  12. ↑ "Prof Graeme Clark AO". Royal Institution of Australia.
  13. ↑ The Lasker-Debakery award for clinical medical research was awarded jointly to Graeme Clark, Ingeborg Hochmair, and Blake Wilson "for the development of the modern cochlear implant"
  14. ↑ Lasker Foundation honours cochlear-implant pioneers
  15. ↑ "Graeme Clark wins 2011 CSL Florey Medal". Australian Institute of Policy and Science. 21 November 2011. Retrieved 2 December 2011. Professor Clark had a big idea and took it through a torturous scientific and regulatory path to create a device that has transformed the lives of people around the world. His ideas have seeded many other initiatives in bionics
  16. ↑ Cochlear implant pioneer wins surgical award, (Press release), Royal College of Surgeons of England , 2 November 2010, Retrieved February 2011

External links

  1. Sounds from Silence: Autobiography by Graeme Clark http://books.google.com/books?hl=en&id=qeuUoRlvJOYC&dq=sounds+from+silence:+graeme+clark&printsec=frontcover&source=web&ots=XJvVi1I8Qu&sig=gkccUH3AMnEtqUFOG2zWVGib7os&sa=X&oi=book_result&resnum=1&ct=result
  2. Cochlear Implants : Fundamentals and Applications: by Graeme Clark: (written by the "father" of the multiple-channel cochlear implant, this comprehensive text and reference gives and account of the fundamental principles underlying cochlear implants and their clinical application. It thus discusses work in all relevant disciplines. http://catalogue.nla.gov.au/Record/1009944
  3. The University of Melbourne Find an Expert (Graeme Clark): http://www.findanexpert.unimelb.edu.au/researcher/person15904.html
  4. National Library ASAP entry: http://www.asap.unimelb.edu.au/bsparcs/archives/P001420a.htm
  5. National Library Graeme Clark papers: http://www.nla.gov.au/ms/findaids/8696list.html
  6. National Library Pandora Graeme Clark Web archive: http://pandora-search.nla.gov.au/apps/textsearch/action/searchget?query=Graeme+Clark&x=38&y=4
  7. Graeme Clark research and development process: http://www.powerhousemuseum.com/hsc/cochlear/research.htm
  8. About Graeme Clark – Cochlear: http://www.cochlear.com/wps/wcm/connect/au/about/company-information/history/about-graeme-clark
  9. Graeme Clark Cochlear Scholarship: http://www.cochlear.com.au/Corp/Press/236.asp and http://www.cochlear.com.au/Community/600.asp and http://www.cochlearamericas.com/Support/168.asp
  10. "The Bionic Ear Institute." People in Our Group. 8 Nov 2008 http://www.bionicear.org/people/clarkg/
  11. Senior Australian of the Year award: http://www.australianoftheyear.org.au/pages/page116.asp
  12. Boyer lectures (Graeme Clark): http://catalogue.nla.gov.au/Record/4274036
  13. "Boyer Lectures." ABC Radio National. 8 Nov 2008 http://www.abconline.net.au/rn/boyerlectures/stories/2007/about/
  14. The Graeme Clark Charitable Foundation: http://graemeclarkfoundation.org/default.htm
  15. Inaugural Graeme Clark Oration: http://ict4lifesciences.org.au/inaugural-graeme-clark-oration.html and
  16. Inaugural Graeme Clark Oration http://nicta.com.au/__data/assets/pdf_file/0017/18035/NICTA_News_Iss16_Final_Art.pdf
  17. Graeme Clark Forum Australian Research Council, Canberra: http://www.research-outcomes.com.au/article.php?article=5,101
  18. Graeme Clark Centre for Innovation in the Sciences- Scots College, Sydney: http://www.tsc.nsw.edu.au/docs/user/1324.pdf
  19. The Graeme Clark Centre for Bionic and Neurosensory Research: http://www.latrobe/news/articles/2009/article/bionic-ear-launch