- Graeme Clark Collection
Graeme Clark Collection
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ItemResults in children using the 22 electrode cochlear implant [Abstract]Dawson, Pam W. ; Blamey, Peter J. ; Clark, Graeme M. ; Busby, P. A. ; Rowland, L.C. ; Dettman, S. J. ; Brown, A. M. ; Dowell, Richard C. ; Rickards, Field W. ; Alcantara, Joseph I. ( 1989)Abstract not available due to copyright.
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ItemRecent developments with the Nucleus 22-electrode cochlear implant: a new two formant speech coding strategy and its performance in background noiseFranz, Burkhard K-H. G. ; Dowell, Richard C. ; Clark, Graeme M. ; Seligman, Peter M. ; Patrick, James F. ( 1987)A clinical evaluation of speech processing strategies for the Nucleus 22-electrode cochlear implant showed improvements in understanding speech using the new F0F1F2 speech coding strategy instead of the F0F2 strategy. Significant improvement in closed-set speech recognition in the presence of background noise was an additional advantage of the new speech processing strategy.
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ItemEvaluation of a two-formant speech-processing strategy for a multichannel cochlear prosthesisDowell, R. C. ; Seligman, P. M. ; Blamey, P. J. ; Clark, Graeme M. ( 1987)Initial results with the two-formant speech-processing strategy (F0FIF2) confirm the advantage of a multichannel cochlear prosthesis capable of stimulating at different sites within the cochlea. The successful presentation of two spectral components by varying the place of stimulation leads to the possibility of presenting further spectral information in this manner. Because virtually all multichannel implant patients demonstrate good "place" (electrode site) discrimination, these more refined coding strategies should lead to benefits for the majority of implantees. Already, with the F0FIF2 strategy, we have a system that appears to provide some effective auditory-alone communication ability for the average patient.
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ItemA multiple-electrode intracochlear implant for childrenClark, Graeme M. ; Blamey, Peter J. ; Busby, Peter A. ; Dowell, Richard C. ; Franz, Burkhard K-H. ; Musgrave, Gaye Nicholls ; Nienhuys, Terry G. ; Pyman, Brian C. ; Roberts, Susan A. ; Tong, Yit C. ; Webb, Robert L. ; Kuzma, Januz A. ; Money, David K. ; Patrick, James F. ; Seligman, Peter M. ( 1987)A multiple-electrode intracochlear implant that provides 21 stimulus channels has been designed for use in young children. It is smaller than the adult version and has magnets to facilitate the attachment of the headset. It has been implanted in two children aged 5 and 10 years. The two children both lost hearing in their third year, when they were still learning language. Following implantation, it was possible to determine threshold and comfortable listening levels for each electrode pair. This was facilitated in the younger child by prior training in scaling visual and electrotactile stimuli. Both children are regular users of the implant, and a training and assessment program has been commenced.
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ItemTwo-component hearing sensations produced by two-electrode stimulation in the cochlear of a deaf patientTong, Y. C. ; Dowell, R. C. ; Blamey, P. J. ; Clark, Graeme M. ( 1983)http://www.sciencemag.org/cgi/content/abstract/219/4587/993?ijkey=v6jEOhdpzPCxw&keytype=ref&siteid=sci
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ItemPsychophysical studies evaluating the feasibility of a speech processing strategy for a multiple-channel cochlear implantTong, Y. C. ; Blamey, P. J. ; Dowell, R. C. ; Clark, Graeme M. ( 1983)Abstract not available due to copyright.
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ItemThe clinical trial of a multi-channel cochlear prosthesisPyman, B. C. ; Clark, Graeme M. ; Dowell, R. C. ; Webb, R. L. ; Brown, A. M. ; Bailey, Q. E. ; Luscombe, S. M. ( 1983)The results of a multiple-electrode cochlear implant carried out on 1st August, 1978 on a totally deaf patient (post-lingual hearing loss) showed that he could perceive sounds of different pitches depending on the electrode stimulated, and this finding was consistent with the place theory of frequency coding. Furthermore, stimulating individual electrodes produced percepts which the patient described as vowel-like in quality. The patient could also perceive different pitches which varied with the rate of stimulation up to 200 pulses/second, but at higher rates he had difficulties perceiving pitch changes (Clark et al. 1978; Tong et al, 1979). As a result of the psychophysical studies a speech processor was developed. The speech processor extracted: firstly, the voicing frequency to help the patient hear the rhythm of speech and know whether a speech sound was voiced or unvoiced (e.g., /b/ versus /p/); and, secondly, the second formant to enable the patient to recognize vowels and consonants and so hear words. In order to maximize speech intelligibility, the second formant stimulated an appropriate electrode, and the rate of stimulation on that electrode was related to the voicing frequency.
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ItemPreoperative hearing aid evaluations for cochlear implant patients: a preliminary report using a minimal auditory capabilities batteryMartin, L. F. A. ; Dowell, R. C. ; Clark, Graeme M. ( 1983)Two profoundly deaf patients were evaluated using the Minimal Auditory Capabilities (MAC) battery of speech discrimination tests. One patient was a multiple-channel cochlear implant patient (MC1) using a wearable speech-processor, the other a prospective cochlear implant patient using a hearing aid (HA). Results from the MAC battery showed that MC1 received significantly more auditory information via the speech-processor than was provided by the hearing aid to HA. These results indicated that the cochlear implant could be a suitable alternative for HA. However, the results indicated that HA gained some minimal benefit from the hearing aid and these results should be taken into consideration when deciding which ear should be implanted.
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ItemInitial results for six patients with a multiple-channel cochlear prosthesisDowell, R. C. ; Brown, A. M. ; Seligman, P. M. ; Clark, Graeme M. (Monash University Press, 1983)A total of eight patients have been assessed with the multi-channel cochlear prosthesis at the University of Melbourne. The first two patients were implanted with a prototype device in 1978 and 1979, and their results with various speech evaluation procedures have been reported and summarized in detail elsewhere (Clark & Tong, 1982). Briefly, these results indicated that some very significant benefit could be obtained for these patients when using the cochlear prosthesis with external speech processing, particularly when using the device in conjunction with lipreading. It was also shown that some significant understanding of speech was possible without lipreading (open-set) for both patients, although this was fairly limited.
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ItemClinical results with a multichannel pseudobipolar systemClark, Graeme M. ; Tong, Y. C. ; Dowell, R. C. ( 1983)A receiver-stimulator and multiple-electrode array were implanted in the scala tympani of a 46-year-old totally deaf man on August 1, 1978. This patient had lost all hearing after a head injury 18 months prior to surgery. Pure-tone Bekesy and speech audiometry showed no hearing in either ear at the maximum output levels of the audiometer, and no vibrotactile responses were elicited. A second patient, a 63-year-old man, received an implant on July 17, 1979. This patient had a progressive sensorineural hearing loss extending over 30 years due to bomb blast and chronic infection. He had no help from a hearing aid for 13 years prior to surgery. Pure-tone Bekesy audiometry under headphones revealed no hearing in the left ear, and in the right he had thresholds of 125 dB SPL at 0.125 kHz; 115 dB at 0.25 kHz, and 117 dB at 0.5 kHz. There was no speech discrimination in either ear under headphones or in a monitored sound field. His right ear was fitted with a hearing aid (Calaid G12G) by the National Acoustics Laboratory, but at its maximum output level he received only a limited gain at 5.0 kHz and could not be aided. (From Introduction)