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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ItemA multiple-channel cochlear implant: an evaluation using an open-set word test( 1981)Multiple-channel electrical stimulation of the hearing nerve in conjunction with speech reading has helped two post-lingually deaf patients with total hearing losses understand running speech in every day situations. This has been confirmed using open-set phonetically balanced word tests, where the patients achieved 60% and 40% scores with isolated-words and 80% and 73% for phonemes-in-isolated words. The tests also showed that the cochlear implant improved word recognition by a factor of four in one patient and two in another compared with speechreading alone. The speech processor used extracted the voicing frequency and energy and the frequency and energy of the dominant spectral peak in the mid-frequency range. The parameters for voicing determined the rate of stimulation for all electrodes, and the parameters for the dominant spectral peak in the midfrequency range determined the site of electrode stimulation and current level.
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ItemSpeech processing for a multiple-channel cochlear implant( 1980)A laboratory speech processor has been developed for a multiple-channel cochlear implant prosthesis. The speech processor accepts the speech waveform as an input and produces a pattern of electrical stimulus data as output. The electrical stimulus data are transmitted to the implanted receiver-stimulator by a transmitter which is external to the speech processor. Four speech signal parameters were estimated every 20 ms in the parameter estimation section of the speech processor. These parameters included the fundamental frequency (FO), a low frequency energy measure (AO) , the second formant frequency (F2) and its amplitude (A2).
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ItemPsychophysical studies for a multiple-channel cochlear implant( 1980)This paper describes the results obtained in a series of psychophysical studies conducted with our first multiple-channel cochlear implant patient. The variations of apparent loudness and pitch for single-electrode stimulation were determined by the method of magnitude estimation. The results showed that the loudness growth due to increases in current level was much steeper than the growth for acoustic stimulation in normal hearing subjects. The pitch produced by electrical stimulation was found to increase with pulse rates below 200 pps, while the increase in pitch with pulse rate was less pronounced above 200 pps. For a constant rate of stimulation, the pitch varied with the electrode position. Furthermore, the same pitch estimate could be obtained by driving single electrodes with different pulse rates.
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ItemSpeech processor design for a multiple-channel cochlear implant( 1980)This paper outlines the strategy adopted for a laboratory-based speech processor used to provide speech information to patients with a multiple-channel cochlear implant It also presents the results of vowel and consonant recognition studies and speech test using open sets of words and sentences.
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ItemSpeech processing for a totally deaf patient with a multiple-electrode cochlear implant [Abstract]( 1980)A patient with a total hearing loss had a multiple-electrode cochlear implant performed on 1 August 1978 (Clark et. Al. 1979). Preliminary findings (Tong et al 1979) have shown that low and high pitch are discriminated on a place basis. Stimulating different electrodes produced the vowel colours.......
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ItemResults in children using the 22 electrode cochlear implant [Abstract]( 1989)Abstract not available due to copyright.
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ItemPsychophysical studies on cochlear implant patients deafened prior to 4 years of age [Abstract]( 1989)Abstract not available due to copyright.
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ItemResults for two children using a multiple-electrode intracochlear implant( 1989)Abstract not available due to copyright.
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ItemPerceptual studies on cochlear implant patients with early onset of profound hearing impairment prior to normal development of auditory, speech, and language skills( 1988)Abstract not available due to copyright.