Multi-electrodes cochlear implant
Historical reality

by Professor Claude-Henri CHOUARD

Text available in French

At the beginning of the 1970s, American, Australian and Austrian researchers were neck and neck in this challenge and seemed close to succeeding because they had verified the biocompatibility of the materials (thin platinum-iridium electrodes coated with Teflon, silastene® perfectly supported by the tissues). But they did not dare to apply their knowledge to humans because they did not know how to transfer the results of their favorable laboratory tests to the vast spaces of normal daily life. Moreover, they feared a reactionary degeneration of the cochlear fibers that some famous authors believed they had observed in their histological collections. Finally, many otologists felt that the single electrode of William Hause was safe and sufficiently effective.

The multi-electrodes cochlear implant was born in the ENT Department of the Paris-Saint-Antoine University Hospital on September 22, 1976

Professor Claude-Henri Chouard, at the time Deputy Head of this ENT department, had already tackled the problem in 1971. He had the idea of asking Professor Patrick MacLeod, Director of Research at the École Pratique des Hautes Études and sensory electrophysiologist, to help him solve the dilemma encountered by all the foreign teams in the rest of the world. Thus, MacLeod first defined the physiological objectives that needed to be achieved regarding the electrical isolation of the electrodes from each other, the transfer of electrical energy through the skin, and the placement in the tympanic ramp and on the cochlear keyboard of the electrodes so that the speech frequencies could be perceived by the patient. Chouard responded to these requirements by inventing an original surgical approach leading to each of these frequency zones in the tympanic ramp by developing a method of isolation using small blocks of silastene® placed in each site of the tympanic ramp. The electrical tightness of this process was quickly verified in vitro on a human rock.

 
This 2021 pdf tells the story of the invention through the career of its inventor

The multi-electrodes cochlear implant was declared to the scientific world at the XII International Congress of ENT held in Buenos Aires in 1977. The corresponding patent was granted on March 16, 1977.

Patent n°77 07824 of 1977

Patent n°85 13528 of 1985

This pdf gives further evidence of anteriority

The invention, from its birth, aroused great interest from the media and the general public: the 1978 book Entendre Sans Oreille (Hearing Without Ears) allows to relive the birth of the invention.

This book is the story of the birth of a discovery and of the long research that follows, with its trials and tribulations, its doubts, its anxieties, its incessant struggles against what, yesterday, still appeared to be the impossible : hearing without the ears. This book is also the intimate testimony of a man entirely devoted to his patients and who dedicates his life to them.

Information mail written taking into account the modification of the code of ethics of French doctors by the decree of December 22, 2020, in order to lift the general and absolute ban on advertising made necessary by a ruling of the Court of Justice of the European Union on May 4, 2017.