Claude-Henri Chouard has made personal contributions to all three fields in which he has worked. The first two fields have often required him to draw on his surgical experience and
clinical empathy.
The multichannel cochlear implant The multichannel cochlear implant was designed and developed in 1975 at Saint-Antoine Hospital by a multidisciplinary team formed by Patrick MacLeod and Claude-Henri Chouard for this very purpose. For over eight years, these researchers were well ahead of all the other international teams, until the collapse of French company Bertin temporarily put paid to their progress. However, the core principles established by the researchers in the patents taken out by
Bertin Technologies in 1977 are still used by today's manufacturers of multichannel implanted auditory prostheses, both intracochlear and auditory brain stem. the device never managed to enable patients to identify words without
lip reading. After twelve years of trials, the researchers all agreed on one thing: to achieve the level of performance required to give these patients a comfortable social life, the cochlear implant would need several electrodes, so it could stimulate the different frequency regions on the "cochlear keyboard", which were identified by 1961
Nobel Prize winner
Georg von Békésy. However, all the researchers hesitated in moving forward, fearful of failure and major complications. In 1973, after closely studying the tentative results achieved thus far, C.H. Chouard and Dr P. MacLeod, who had completed their medical training together, decided to tackle the problem. P. MacLeod was by now a researcher specialising in sensory physiology, while C.H. Chouard had personal experience of performing surgery on the facial and vestibular nerves. They decided to combine these skills and form a multidisciplinary team within the ENT Research Laboratory at Saint-Antoine University Hospital in Paris. In 1975, they performed a fully ethical study on three patients with recent traumatic unilateral total deafness and total facial paralysis, which required surgery. The study showed that selective electrical stimulation of eight to twelve electrodes, each isolated from the others, placed in different locations within the
tympanic duct of the cochlear, resulted in the perception of different frequencies. influenced all the procedures used and research undertaken by other international teams, who were obliged to find ways around the claims—usually by transmitting only part of the speech information—until the patent fell into the public domain in 1997. In 1982, at a meeting organised by the
New York Academy of Sciences to review the multichannel cochlear implant, have been published to address this surprising oversight, referring notably to numerous previous works by the Parisian team. In 1991, MXM-Neurelec presented its first multichannel implant. It was fully digitised and could be adapted to ossified cochleas. The implant was based on the Bertin licence, but its development was very closely guided by suggestions from researchers at the Saint-Antoine ENT Research Laboratory in Paris. From 1992 onwards, the multichannel cochlear implant gradually gained acceptance in France. Today, in 2015, most of the principles established by Claude-Henri Chouard and Patrick MacLeod's team between 1976 and 1977 are still used by all manufacturers of cochlear implants and auditory brain stem implants.
Snoring and obstructive sleep apnoea Between 1984 and 1990, encouraged by his assistants Prof. Bernard Meyer and Fréderic Chabolle, and with the help of pulmonologist Prof. Bernard Fleury and cardiologist Prof. Jean Valty of Saint-Antoine Hospital, Claude-Henri Chouard began studying the symptomatology and epidemiology of the complications of a new disease in the field of ENT. He named this disease chronic
rhonchopathy. The main symptom is snoring, which no one had previously viewed as a relevant sign of disease. In fact, the louder the
snoring, the greater the risk that it is associated with severe obstructive sleep apnoea. After laying the foundations for treatment development with his students, Claude-Henri Chouard ceased to be personally involved in this area of research, leaving the youngest members of his team to continue enhancing our knowledge of this new disease and perfecting the corresponding treatments.
Neuroanatomy During the mid-twentieth century, Charles Eyriès was a researcher in the anatomy laboratory run by Prof. André Delmas, spending his mornings as an ENT surgeon and his afternoons as a neuroanatomist. Claude-Henri Chouard was one of his students between 1960 and 1966. Eyriès taught him Born's method for 3D reconstruction of histological sections at a magnification of 100 and 150. This technique was to prove useful twenty years later, when Chouard showed that children with neonatal deafness need to receive implants as early as possible, before the auditory brain structures begin to atrophy 5. Chouard became familiar with total deafness very early on in his career, since he had direct access to information on the famous electro-therapeutic trials performed by Eyriès in 1957 with André Djourno. Claude-Henri Chouard also identified the functional origins of acoustico-facial anastomoses by following the reconstructed nerve fibres from one end to the other. This helped explain the effectiveness of certain treatments for
Menière's disease he observed that the nucleus of the last brachial nerve, the pneumogastric nerve, extended a long way down, undoubtedly causing afferent sensitivity of the enteric and airway pathways. This hypothesis has been the electro-physiological existence of which was recently demonstrated within the intestines, and which could potentially play a role in certain forms of diabetes. == Academic Work ==