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CHAPTER 1. History of Cochlear Implants
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CHAPTER 1 History of Cochlear Implants with Patricia Elizabeth Spencer By the middle of the 20th century, the medical profession had made great strides in understanding important physiological aspects of hearing, but nevertheless had little to offer people who experienced a profound sensorineural hearing loss (frequently, but inaccurately , called “nerve deafness”). The first attempt to achieve auditory sensation through electrical stimulation probably occurred two centuries ago when Italian Count Alessandro Volta inserted metal rods in his ear canals and connected them to an electric circuit (an unpleasant experience he seldom repeated—“a boom within the head” [Niparko & Wilson, 2000]). However, little occurred between 1800 and the mid-1900s to give profoundly deafened people any indication that their hearing could be even partially restored (Beiter & Shallop, 1998;Blume, 1999;Epstein, 1989; House & Berliner, 1991). The first modern attempt to electrically stimulate the auditory nerves in the cochlea 1 occurred early in 1957, in Paris, when French otologist Charles Eyries and his colleague A. Djourno implanted an electrode in a man who was eager to have at least a minimal sensation of sound. Under local anesthesia, the electrode 1. An explanation of the function of the cochlea, what a cochlear implant does, the surgical procedure, the equipment involved, and other technical matters is found in chapter 2. 15 was placed on the bony wall that separates the middle ear from the cochlea. After subsequent electrical stimulation, the patient reported hearing a few different sounds and some common words. The effect was not sustained, however, and the implant was eventually explanted (Beiter & Shallop, 1998;Blume, 1999;Nevins & Chute, 1996). Four years after Eyries and Djourno performed their surgery in France, William House, an otologist in Los Angeles, and his colleague James Doyle made another attempt to electrically stimulate the auditory nerve endings in the cochlea. House and Doyle implanted several adult deaf volunteers in 1961, and one of them received a multichannel cochlear implant.2 The purpose of this early multichannel implant was to attempt to provide some speech discrimination. This implant “stimulated the cochlea at five different positions along its length, each sensitive to a different range of frequencies” (Blume, 1999, p. 1258). After additional trials, House decided to focus on a single-channel cochlear implant rather than a multichannel one because he felt that single- and multichannel implants could be equally effective (House, 1995). However , virtually all of the cochlear implants today are multichannel models that have, as their goal, the type of speech discrimination that was of interest to House 40 years ago. Ultimately, because of technical problems with the insulating material, House and Doyle’s early implants were unsuccessful and had to be removed (House & Berliner, 1991). Several years after his first effort, House teamed up with Jack Urban, an electrical engineer, and tried again. In 1969 and 1970, House and Urban implanted three adult patients with multichannel devices that were constructed with insulation material that had been perfected in the 1960s for use with heart pacemakers. These cochlear implant surgeries were somewhat more successful than earlier attempts in that the patients experienced a sustained sensation of sound; still, House and Urban focused on developing a 16 COCHLEAR IMPLANT HISTORY AND TECHNOLOGY 2. Cochlear implants are either multichannel or single-channel. Multichannel implants feature a number of electrodes on the electrode array that is inserted into the cochlea, whereas single-channel implants have only one electrode pair. A more detailed discussion of single- and multichannel implants, as well as the difference between an electrode and a channel, is found in in chapter 2. [35.175.121.135] Project MUSE (2024-03-29 15:50 GMT) single-channel implant (House, 1995). Other researchers in the United States, France, and Australia, however, continued to work on the development of a multichannel device.In addition to House and his colleagues, the most important North American contributors to cochlear implant research during the latter part of the 1960s and the early 1970s were F. Blair Simmons and RobertWhite at Stanford University, Donald Eddington at the University of Utah, and Robin Michelson, Michael Merzenich, and Robert Schindler at the University of California, San Francisco (House & Berliner, 1991; Schindler, 1999). Most of these researchers focused their attention on the development of a multichannel device that could, according to Schindler (1999, pp. 5–6), “provide speech understanding to totally deaf persons.” Reaction from the Scientific Community In the 1960s and well into the 1970s, there was a considerable amount of skepticism about the efficacy of cochlear implants...