Graeme Clark Collection

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Subject: speech perception × Subject: cochlear implant × Start date: 1981 × End date: 1989 × Type: Journal Article ×

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    The clinical trial of a multi-channel cochlear prosthesis
    Pyman, 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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    Preoperative hearing aid evaluations for cochlear implant patients: a preliminary report using a minimal auditory capabilities battery
    Martin, 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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    Clinical trial of a multiple-channel cochlear prosthesis: an initial study in four patients with profound total hearing loss
    Bailey, Quentin R. ; Seligman, Peter M. ; Tong, Yit. C. ; Clark, Graeme M. ; Dowell, R. C. ; Brown, Alison M. ; Luscombe, Susan M. ; Pyman, Brian C. ; Webb, Robert L. ( 1983)
    The clinical trial of a multiple-channel cochlear prosthesis was undertaken in four patients with postlingual deafness and profound total hearing loss. The results of open-set speech tests confirmed that, using electrical stimulation alone, one patient could have a meaningful conversation with resorting to lipreading (for example, this patient uses the prosthesis to converse with her husband on the telephone). The results of closed-set speech tests also suggested that a multiple-channel stimulator is more effective than a single-channel one in conveying speech information. The cochlear prosthesis was especially effective in all four patients when it was used in conjunction with lipreading, and speech-tracking tests showed that the patients could combine the information obtained from both electrical stimulation and lipreading.
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    A multiple-channel cochlear implant and wearable speech-processor: an audiological evaluation
    Tong, Y. C. ; Clark, Graeme M. ; Dowell, R. C. ; Martin, L. F. ; Seligman, P. M. ; Patrick, J. F. ( 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.