The history of electrical stimulation of the auditory system can be traced to a number of early experiments in electricity and in neurophysiology (see Simmons,1 Chapter 1). However, the event most frequently cited as inspiring the development of the auditory prosthesis was the experiment published in 1957 by Djourno and Eyries,2 who implanted wires in the inner ear of a deaf patient and were able to produce sensations of sound by electrical stimulation. The experiment was subsequently tried by Doyle et al.3 in Los Angeles and then by William House4 and investigators at the House Ear Institute. It was House who was most enthusiastic about this procedure, and he eventually developed, and achieved FDA approval for, a single channel cochlear implant.5 Blair Simmons, at Stanford University, first implemented the concept of a multichannel implant. He placed a set of four wires directly into the auditory nerve.6 Shortly thereafter Robin Michelson at the University of California San Francisco implemented a multichannel implant placed in the scala tympani of the cochlea.7 The UCSF implant, developed and subsequently modified by a research team under the leadership of Michael Merzenich, helped establish and test many of the design concepts and hypotheses that have led to the current generation of prosthesis.8 The UCSF laboratories also began the development9 of what is now the Clarion® prostheses, manufactured by Advanced Bionics® Corporation.10,11

In the meantime, a large and very productive research program was developing at the University of Melbourne in Australia under the leadership of Graeme Clark.12 The implants resulting from this research program are manufactured by Cochlear Ltd., a subsidiary of Nucleus Pty. Ltd. in Sydney. Cochlear Ltd. currently has the largest population of implant users worldwide (over 23,000 patients).

Other implants have been brought to market as a result of research in London;13 Salt Lake City, UT (the Ineraid prosthesis);14,15 Vienna and Innsbruck, Austria (the Combi 40+ prosthesis manufactured by Med-El);16-18 Paris (the Digisonic® prosthesis manufactured by MXM);19 Antwerp, Belgium (the Laura prosthesis manufactured by Philips Hearing Technologies, B.V.);20,21 and elsewhere.

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