Graeme Clark Collection
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ItemThe effects of electrode position and stimulus period on the hearing sensations in a multiple-channel cochlear implant patient [Abstract]( 1981)Abstract not available due to copyright.
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ItemPerceptual dissimilarity and discrimination studies using two-electrode stimulation with a multiple-channel cochlear implant patient [Abstract]( 1981)Abstract not available due to copyright.
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ItemPitch and loudness studies on a multiple-channel cochlear implant patient [Abstract]( 1981)Abstract not available due to copyright.
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ItemSpeech feature encoding through an electrotactile speech processor [Abstract]( 1989)Abstract not available due to copyright.
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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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ItemSpeech feature recognition by profoundly deaf children using the University of Melbourne multichannel electrotactile aid [Abstract]( 1989)Abstract not available due to copyright.
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ItemPreliminary evaluation of a wearable multichannel electrotactile speech processor [Abstract]( 1988)Speech discrimination testing, using both open-and closed-set materials was carried out with four severely-to-profoundly hearing impaired adults. and seven normally hearing subjects, to assess performance of a wearable eight-channel electrotactile aid (Tickle Talker). The device consisted of a handset composed of nine electrodes, a stimulator-unit, and a speech processor and input microphone. Eight small electrodes were located over the digital nerve bundles on each side of the four fingers of one hand, and a larger common electrode was placed on the wrist. Subjects perceived eight separate channels of information, each corresponding to a stimulus on one side of one finger. The speech processor provided estimates of second formant frequency, fundamental frequency and amplitude of the speech waveform. These features were coded as electrode position, pulse rate and pulse width respectively. This processing strategy (FOF2AO) is similar to that used in an earlier model of the Cochlear Pty. Ltd. cochlear implant.
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ItemSpeech perception with cochlear implants and tactile aids [Abstract]( 1988)Abstract not available due to copyright.
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ItemEvaluation of training strategies with an electrotactile speech processor [Abstract]( 1988)During 1986, seven normally-hearing subjects were trained in the use of an electrotactile speech processor ("Tickle Talker"). Two training methods were used: (a) a combined strategy. in which a variety of training materials ranging from analytic to synthetic level were employed; and (b) a synthetic alone training strategy, in which only synthetic level training materials were used. All seven subjects received 70 hours of training, 35 hours in each training strategy. Subjects were evaluated in the tactile-lipreading (TL) and lipreading alone (L) conditions at: (I) 0 hours training; (2) 35 hours training; and (3) after 70 hours of training. An evaluation test battery was constructed which contained both closed-set and open-set materials. Results indicated differences in performance on the evaluation tests which were dependent upon the training strategy. The differences in performance were greater in some evaluation tests than others. Subsequently; seven severe-profoundly hearing-impaired children (aged 7-11) have been fitted with the Tickle Talker and are presently participating in an ongoing training programme. Evaluation of their performance will help to assess the suitability of the device for young children.
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ItemSpeech recognition performance with a two-formant coding strategy for a multi-channel cochlear prosthesis [Abstract]( 1986)Over the last two years, a new speech coding strategy (F0F1F2) has been developed for the Nucleus multi-channel cochlear prosthesis designed to provide information about the first formant, in addition to the second formant and voicing frequency information provided by the “standard” speech processing strategy (F0F2). This strategy uses quasi-simultaneous stimulation of two electrode pairs within the cochlea at the voice pitch rate. The positions of the two sites of stimulation vary independently according to the frequencies of the first and second formants. The amplitude at each site is determined from the first and second formant amplitudes. Seven patients were changed to this strategy and an initial study showed significant improvements in recognition of open set sentence material (from a mean of 30.4% for F0F2 to 62.9% for F0F1F2) and for speech tracking without lipreading (from 11.8 wpm to 30.5 wpm). Phoneme recognition investigations indicated that: 1) vowel identification was improved due to the addition of first formant frequency information in the new strategy, 2) consonant identification was also improved, due to the extra information provided by the independent variation of the amplitude components. These encouraging results led to the use of the F0F1F2 strategy for all new patients from April 1985. Results for recorded speech testing (MAC battery) three months after surgery have been compared for 13 patients who used the F0F1F2 strategy. Significant improvements were observed for the F0F1F2 group on most of the tests. Mean scores for open set testing were as follows: a) spondee recognition: 13.6% for F0F2 and 26.0% for F0F1F2, b) CID sentences: 15.9% for F0F2 and 37.8% for F0F1F2, c) monosyllabic words: 4.9% for F0F2 and 12.4% for F0F1F2, d) phoneme recognition: 23.1% for F0F2 and 33.4% for F0F1F2.