Graeme Clark Collection

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    A clinical report on speech production of cochlear implant users [Abstract]
    Dawson, P. ; Blamey, P. ; Dettman, S. ; Rowland, L. ; Barker, E. ; Tobey, E. ; Busby, P. ; Cowan, R. ; Clark, Graeme M. ( 1994)
    Speech production results are reported for a group of 15 children, adolescents and prelinguistically deafened adults implanted with the 22-electrode cochlear implant. Age at implantation ranged from 5 years to 20 years and implant experience ranged from 1 year to 4 years, 7 months. On a speech intelligibility test using sentences seven implant users improved significantly over time. Mean group performance (n = 11) improved from 18% preoperatively to 43% postoperatively. Similarly on a test of articulation, eight implant users improved significantly over time and the group mean postoperative performance (n = 11) exceeded the preoperative performance (55% compared to 38%). This group effect was significant for consonants and blends but was nonsignificant for vowels. Improvements occurred for front, middle and back consonants, for stops, nasals, fricatives and glides and for voiceless and voiced consonants. Three implant users showed no significant gain on either test. The results suggest complex relationships between speech production performance and sensory information provided by a multichannel implant.
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    The effects of auditory feedback from the nucleus cochlear implant on the vowel formant frequencies produced by children and adults
    Richardson, Louise M. ; Busby, Peter A. ; Blamey, Peter J. ; Dowell, Richard C. ; Clark, Graeme M. ( 1993)
    Cochlear implants provide an auditory signal with which profoundly deaf users may monitor their own speech production. The vowel production of two adults and three children who used the Nucleus multiple-electrode cochlear implant was examined to assess the effect of altered auditory feedback. Productions of words were recorded under conditions where the talkers received auditory feedback (speech processor turned on) and where no auditory feedback was provided (speech processor turned off). Data were collected over 3 days at weekly intervals. First and second formant frequencies were measured and the data were analysed to assess significant differences between auditory feedback conditions, vowel context, and data collection points. Overall, the results varied across talkers, across the data collection days, and depended on the consonant environment of the vowel. However, two effects of auditory feedback were noted. First, there was a generalized shift in first formant frequencies between the processor on and processor off conditions across three of the five subjects, but the shift differed in direction for each subject. Second, for three of the five talkers, the two front vowels /ε/ and /I/ were more neutralised in the absence of auditory feedback. However, this effect was less pronounced than that noted by previous studies.
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    Results of speech perception and speech production training for three prelingually deaf parents using a multiple-electrode cochlear implant
    Busby, P. A. ; Roberts, S. A. ; Tong, Y. C. ; Clark, Graeme M. ( 1991)
    Five studies were conducted to measure changes in the perception and production of selected speech targets, with training, in three prelingually deaf patients. The two adults and one adolescent were implanted with the Cochlear (Nucleus) multiple-electrode prosthesis. The studies were perception and production of nasal consonants; perception of syllable-final consonants; perception and production of alveolar consonants; auditory-visual perception of alveolar consonants; and perception and production of vowels. Perceptual data were collected in the audition (implant)-alone condition, except for the auditory visual perception of alveolar consonants where the audition-alone, vision-alone, and auditory-visual conditions were used. Speech perception data in the audition-alone condition were also collected from four postlingually deaf adult implant patients, without training, to indicate differences between the two classes of patients. The three prelingually deaf patients generally showed some improvements in speech production. In perception, improvements were recorded only for individual patients in some studies. The performance of the adolescent was better than that of the two adults in all cases. The perceptual performance of the postlingually deaf patients was superior to that of the prelingually deaf patients in all cases.
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    Results for two children using a multiple-electrode intracochlear implant
    Busby, P. A. ; Tong, Yit C. ; Roberts, S. A. ; Altidis, P. M. ; Dettman, S. J. ; Blamey, Peter J. ; Clark, Graeme M. ; Watson, R. K. ; Rickards, Field W. ( 1989)
    Abstract not available due to copyright.
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    Speech perception, production and language results in a group of children using the 22-electrode cochlear implant
    Busby, P. A. ; Brown, A. M. ; DOWELL, RICHARD ; Rickards, Field W. ; Dawson, Pam W. ; Blamey, Peter J. ; Rowland, L.C. ; Dettman, Shani J. ; Altidis, P. M. ; Clark, Graeme M. ( 1989)
    Paper presented at the 118th Meeting of the Acoustical Society of America
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    Results for the Nucleus multiple-electrode cochlear implant in two children [Abstract]
    Tong, Y. C. ; Blamey, P. J. ; Dowell, R. C. ; Nienhuys, T. G. ; Musgrave, G. N. ; Busby, P. A. ; Roberts, S. A. ; Rickards, F. W. ; Dettman, S. J. ; Altidis, P. M. ; Clark, Graeme M. ( 1988)
    Two males, 9 years 10 months (CHILD 1) and 5 years 5 months (CHILD 2) at time of surgery, were implanted with the Nucleus multiple-electrode cochlear implant. Both patients were deafened as a result of meningitis in their third year. Assessments of speech perception, speech production and language skills were undertaken at regular intervals, pre and post operatively. For both patients in the audition alone condition, some speech perception post operative scores were significantly higher than pre operative scores and progressive improvements in scores over successive post operative data collection times were seen. Significant differences between the visual alone and auditory-visual condition scores were also observed for CHILD 1 post operatively. Speech production post operative scores were significantly higher than pre operative scores for both patients. The receptive vocabulary scores for both patients improved at a higher rate than that of age-matched normal children. The acquisition of expressive and receptive language skills for CHILD 2 was at a higher rate than that of age-matched children. Differences in the results between the two patients were seen, and this may be related to age and duration of deafness.