Graeme Milbourne Clark AC (born 16 August 1935 in Camden, New South Wales) is an Australian doctor. He was a key figure in the research and development of the Bionic Ear – a multiple-channel cochlear implant.
Clark was born in Camden, New South Wales, and was educated at the The Scots College. He studied medicine at Sydney University.
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". 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.
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.