Graeme Clark Collection
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ItemA multiple-channel cochlear implant: an evaluation using nonsense syllables( 1981)A study using nonsense syllables has shown that a multiple-channel cochlear implant with speech processor is effective in providing information about, voicing and manner and to a lesser extent place distinctions. These distinctions supplement lipreading cues. Furthermore, the average percentage improvements in overall identification scores for multiple-channel electrical stimulation and lipreading compared to lipreading alone were 71% for a laboratory-based speech processor and 122 % for a wearable unit.
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ItemCurrent distribution measurements within the human cochlea( 1981)The magnitudes of tile currents returned through each ground electrode line of a multiple-electrode cochlear implant array were determined during surgical implantations on two patients. These were often found to be distributed widely to points far from the stimulus electrode site. Further measurements made in in vitro solutions demonstrated that the distributions were due largely to the ground electrode interface impedances being significantly larger than the fluid-path impedances, and demonstrated that distributions could be changed by modification of the ground electrode interface impedances.
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ItemPsychophysical and speech perception studies on two multiple-channel cochlear implant patients(Cambridge University Press, 1980)Preliminary studies on our first patient with a multiple channel cochlear implant (Tong et al., 1979) showed that he was able to associate the hearing sensations produced by electrical stimulation of residual auditory nerve fibres with different vowel (spectral) colours. The frequencies characterizing the vowel colours produced by stimulation at single scala tympani electrodes were, in general, closely related to the tonotopical organization of the� cochlea. Furthermore, results from these studies indicated that the pitch produced by single-electrode stimulation increased with pulse rate, and that the loudness increased with current level.
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ItemSpeech processing for a multiple-electrode cochlear implant hearing prosthesis( 1980)Abstract not available due to copyright.
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ItemA preliminary report on a multiple-channel cochlear implant operation(Cambridge University Press, 1979)Intra-cochlear single-channel electrical stimulation has recently been attempted by Michelson (1971) and by House and Urban (1973). Douek et at. (1977) have described experiments with a single-channel promontory electrode system. It is generally accepted that a single-channel system is useful in conveying crude auditory information such as the presence of sounds and some prosodic features of speech (Bilger et al., 1977; Douek et al., 1977). (From Introduction)
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ItemA cochlear implant round window electrode array(Cambridge University Press, 1979)One important aspect of cochlear implantation is the placement of a multiple-electrode array close to residual auditory nerve fibres so that discrete groups of fibres can be stimulated electrically according to the place basis of frequency coding. Furthermore, in patients who are postlingually deaf these electrodes should lie in relation to the nerve fibres which are responsible for transmitting the frequencies which are important in speech comprehension, viz. 300-3,000 Hz. The method of electrode insertion should also ensure that there is no significant damage to auditory nerve fibres.
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ItemA multiple-electrode cochlear implant( 1978)Interest in artificially stimulating the auditory nerve electrically for sensori-neural deafness was first sparked off by Volta in the 18th century. Count Volta, who was the first to develop the electric battery, connected up a number of his batteries to two metal rods which he inserted into his ears. Having placed the rods in his ears he pressed the switch and received "une secousse dans la tete" and perceived a noise like "the boiling of thick soup".
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ItemDesign criteria of a multiple-electrode cochlear implant hearing prosthesis( 1978)Abstract not available due to copyright.
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ItemSpeech processing for cochlear implants(JAI Press Ltd, 1992)The cochlear implant is a hearing prosthesis designed to replace the function of the ear. The operation of the prosthesis can be described as a sequence of four functions: the processing of the acoustic signal received by a microphone; the transfer of the processed signal through the skin; the creation of neural activity in the auditory nerve; and the integration of the experience of this neural activity into the perceptual and cognitive processing of the implantee.
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ItemThe Nucleus 22-channel cochlear implant system( 1991)Cochlear implants have become the treatment of choice for profoundly deaf adults and children who obtain little or no benefit from conventional amplification. Sounds are translated into small electric currents that stimulate the auditory nerves in the cochlea and generate hearing sensations. The Nucleus cochlear implant is the result of more than 20 yr of research and development, first at the University of Melbourne, Australia and later by Cochlear Proprietary Limited (Sydney, Australia) in collaboration with the University of Melbourne. Today, the cochlear Mini-22 implant system is approved by the United States Food and Drug Administration (FDA) for use in adults and children, and has been implanted in more than 3000 patients worldwide. Although this chapter describes the cochlear implant system and clinical issues related to its use in children, much of the material has been derived from experience with adults. Furthermore, the Nucleus system is not static. It is being continually improved both in performance and ease of use. The purpose of this chapter is to describe developments leading up to and including the present Nucleus cochlear implant system. Other chapters in this issue present results and procedures relating to pediatric applications of the device.