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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ItemSpeech processing for a multiple-electrode cochlear implant hearing prosthesis( 1980)Abstract not available due to copyright.
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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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ItemA multiple-channel cochlear implant and wearable speech-processor: an audiological evaluation( 1981)Standard audiological tests were administered to a totally deft multiple-channel cochlear implant patient with a wearable speech-processor in a monitored sound field under the following conditions: a wearable unit activated alone (WA), lipreading with the wearable unit off (LA), and wearable unit activated in combination with lipreading (WL). Thresholds obtained for narrow-band noise signals indicated that the wearable unit allowed the patient to detect a variety of sounds at different frequencies. The results obtained in closed-set word tests and open-set word and sentence tests showed significant improvements in word and sentence scores from LA to WL. In the open-se (C.I.D) sentence tests, the patient scored 22% for LA and 76% for WL. The WL score of 76% correlates with a satisfactory performance in understanding connected speech. The patient also scored 30% correct in a test involving the recognition of environmental sounds.
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ItemA multiple electrode cochlear implant(Cambridge University Press, 1977)It is generally agreed that if a cochlear implant hearing prosthesis is to enable a patient to understand speech, it must be a multiple-electrode system. In addition, stimulation of the auditory nervous system should approximate the patterns of neural excitation occurring in people with normal hearing, and this is especially important when a patient has previously experienced hearing. For this reason the correct application of electrophysiological principles to the design of a hearing prosthesis is desirable, and is discussed in this paper with special reference to a device developed in the Departments of Otolaryngology and Electrical Engineering at the University of Melbourne (UMDOLEE).