Graeme Clark Collection

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    The development of a tympanic membrane sensor for a totally implantable cochlear implant or hearing aid
    Zhang, A. ; Clark, Graeme M. ; Pyman, B. C. ; Brown, M. ; Zmood, R. (Monduzzi Editore, 1997)
    We present the design and development of a tympanic membrane sensor for a totally implantable cochlear implant or hearing aid system. The sensor employs a fiber-optic lever which is hermetically sealed in a biocompatible cartridge and implanted in the middle ear cavity. The sensor prototype has been designed, constructed and tested in cats. In addition, the implantation procedure of the device has also been studied using human temporal bones.
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    Peri-modiolar electrode arrays: a comparison of electrode position n the human temporal bone
    Shepherd, R. K. ; Treaba, C. G. ; Cohen, L. ; Pyman, B. ; Huigen, J. ; Xu, J. ; Clark, Graeme M. (Monduzzi Editore, 1997)
    This paper describes a radiologic evaluation of three types of peri-modiolar arrays, comparing their trajectory within the scala tympani with a standard Mini-22 electrode. All peri-modiolar arrays were found to lie closer to the modiolus for much of their insertion length compared with the standard array. While one design showed evidence for the potential of increased insertion trauma, two designs produced satisfactory results. Although further electrode development, temporal bone and histopathologic studies arE required, it would appear that the benefits of peri-modiolar electrode arrays will be realised clinically.
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    Siting the receiver-stimulator of the CI-24M model of the Cochlear Limited multiple-channel cochlear implant and fixation of its electrode array
    PYMAN, BRIAN ; Clark, Graeme M. (Monduzzi Editore, 1997)
    The correct siting of the cochlear implant receiver-stimulator package is important. The package should not obtrude significantly above the surface of bone, and should be so that blows to the head do not in damage to the package, skull or brain. The cochlear implant electrode array must be fixed at a site close to the cochlea, so that the electrode will not slide out, or be subject to differential movement with growth changes. Fixation, with Dacron® mesh, platinum-iridium ties, or clips, has been in the region of the posterior root of the zygoma and the floor of the antrum. Our research studies demonstrate that a specially-designed collar around the array can be placed through the cochleostomy and provide the necessary locking to prevent retraction of the array. It has a ceramic surround to encourage union with neighbouring bone, and stress relief to reduce wire fracture at the point where the array leaves the cochlea.
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    Multicenter evaluations of speech perception in adults and children with the nucleus (cochlear) 22-channel cochlear implant
    Clark, Graeme M. ; Dowell, Richard C. ; Cowan, Robert S. ; Pyman, Brian C. ; Webb, Robert L. (Kugler, 1996)
    The Nucleus 22-channel cochlear implant has been implanted in over 10,500 patients in 79 countries. and used for more than 25 languages. It arose as a result of our early physiological, behavioral and biological research on experimental animals. The historical development of the Nucleus device has been outlined in detail by Clark. Our ongoing research has led to improvements in the way speech is processed with the 22-channel device that are now resulting in improved speech perception for profoundly totally deaf people that is, on average, better than the speech perception obtained by many deaf people with hearing aids. The multiple-channel cochlear implant was first approved by the US Food and Drug Administration (FDA) for use in postlinguistically deaf adults in 1985. It was subsequently approved for use in children in 1990. The proportion of children (18 years of age and under) to have now received it is approximately 439C (4,500 out of 10.500). In evaluating improvements in speech processing it is important to design well-controlled studies, and a number of important ones which have previously been published are summarized in this paper. In addition, speech perception results for all the Nucleus speech processing strategies have been obtained four to six months postoperatively from unselected patients presenting to the Cochlear Implant Clinic at the Royal Victorian Eye & Ear Hospital (RVEEH), Melbourne, and are presented in this paper. As results can vary greatly with different durations of experience it is essential to make comparisons at the same time postoperatively. These clinical data are the most complete to date for comparing the Nucleus speech processing strategies.