Graeme Clark Collection

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    Phonetic and phonological changes in the connected speech of children using a cochlear implant
    Grogan, M. L. ; Barker, E. J. ; Dettman, S. J. ; Blamey, P. J. ( 1995)
    In excess of 5,000 children, with profound hearing impairment, have received a cochlear implant hearing device. Researchers have recently begun to study the speech production skills of these children.1-6 This topic is of interest because the speech of young prelingually or postlingually deaf children is in a constant state of development. The effectiveness of the implant, therefore, must be measured in its ability to provide enough auditory information for the child to develop intelligible speech. This is in addition to the maintenance of intelligible speech in the case of older postlingually deaf children or adults. The aim of the present study was to investigate some characteristics of the connected speech of a selected group of children from the University of Melbourne Cochlear Implant Programme. More specifically, the study aimed to determine how these characteristics changed over time. Studies of conversational speech samples are useful in that they do not depend on imitation yet they do reflect the child's everyday communication skills and are sensitive to co-articulatory effects. Analyses performed on the preoperative and postoperative data aimed to detect both the phonetic and phonologic changes in the segmental features of speech. The following questions were addressed: 1) What was the pattern of change in the phonetic inventories from before to after implantation? 2) Was there a difference in the correct production of consonants depending on their position in the word? 3) Did the group performance for correct production of phonemes change significantly from before to after implantation? 4) Did performance change over time for individuals? 5) What were the most common phonologic processes and was there a significant reduction in any of these processes from before to after implantation?
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    Vowel imitation task: results over time for 28 cochlear implant children under the age of eight years
    Dettman, S. J. ; Barker, E. J. ; Dowell, R. C. ; Dawson, P. W. ; Blamey, P. J. ; Clark, Graeme M. ( 1995)
    With increasing numbers of implanted children under the age of 4 years, numerous researchers have reminded us of the need for valid, sensitive, and reliable tests of developing speech perception.1,2 In addition to studies of the efficacy of implanted prostheses, there is a need to investigate the many variables that influence children's communicative performance, such as changes in speech-coding strategy, updated speech-processing systems, the effects of various training regimens, and the selection of educational and communication modes.
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    Improved electrotactile speech processor: Tickle Talker
    Cowan, R. S. C. ; Galvin, K. L. ; Sarant, J. Z. ; Millard, R. ; Blamey, P. J. ; Clark, Graeme M. ( 1995)
    The Tickle Talker, an eight-channel electrotactile speech processor, has been developed from continuing research at the University of Melbourne. 'The development of the device has focused on production of reliable speech-processing hardware, design of cosmetically and ergonometrically acceptable electrode transducers, implementation of acute and chronic biomedical studies demonstrating device safety, design and testing of alternative speech-encoding strategies to provide benefit to speech perception and production, and design and testing of appropriate training methods for optimizing benefits. The Tickle Talker has been shown to provide benefits in supplementing lipreading or aided residual hearing for hearing-impaired adults and children. Improvements in speech processing have resulted in an increase in benefits to speech perception, and open the way for more flexible approaches to encoding speech input. Continuing development of the electrode circuitry has now produced a device that is robust and has an extended battery life. Safety studies have clearly demonstrated that there are no long-term contraindications to device use. The results suggest that the device has a role to play in rehabilitation programs for severely and profoundly hearing-impaired adults and children.
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    Habilitation issues in the management of children using the cochlear multiple-channel cochlear prosthesis
    Cowan, Robert S. C. ; Barker, Elizabeth J. ; Dettman, Shani J. ; Blamey, Peter J. ; RANCE, GARY ; Sarant, Julia Z. ; Galvin, Karyn L. ; Dawson, Pam W. ; Hollow, Rod ; Dowell, Richard C. ; PYMAN, BRIAN ; Clark, Graeme M. (Wien, 1994)
    Since 1985, a significant proportion of patients seen in the Melbourne cochlear implant clinic have been children. The children represent a diverse population, with both congenital and acquired hearing-impairments, a wide-range of hearing levels pre-implant, and an age range from 2 years to 18 years. The habilitation programme developed for the overall group must be flexible enough to be tailored to the individual needs of each child, and to adapt to the changing needs of children as they progress. Long-term data shows that children are continuing to show improvements after 5-7 years of device use, particularly in their perception of open-set words and sentences. Habilitation programs must therefore be geared to the long-term needs of children and their families. Both speech perception and speech production need to be addressed in the specific content of the habilitation program for any individual child. In addition, for young children, the benefits of improved speech perception should have an impact on development of speech and language, and the focus of the programme for this age child will reflect this difference in emphasis. Specific materials and approaches will vary for very young children, school-age and teenage children. In addition, educational setting will have a bearing on the integration of listening and device use into the classroom environment.
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    The University of Melbourne/Nucleus cochlear prosthesis
    Clark, Graeme M. ; Blamey, P. J. ; Brown, A. M. ; Busby, P. A. ; Dowell, R. C. ; Franz, B. K-H. ; Millar, J. B. ; Pyman, B. C. ; Shepherd, R. K. ; Tong, Y. C. ; Webb, R. L. ; Brimacombe, J. A. ; Hirshorn, M. S. ; Kuzma, J. ; Mecklenburg, D. J. ; Money, D. K. ; Patrick, J. F. ; Seligman, P. M. ( 1988)
    This is a review of research to develop the University of Melbourne/Nucleus cochlear prosthesis for patients with a profound-total hearing loss. A more complete review can be obtained in Clark et al. A prototype receiver-stimulator and multiple-electrode array developed at the University of Melbourne was first implanted in a postlingually deaf adult patient with a profound-total hearing loss on 1 August 1978. A speech processing strategy which could help this patient understand running speech, especially when combined with lipreading was developed in 1978 following initial psychophysical studies. A prototype wearable speech processor was fabricated in 1979, that could provide significant help for the first two patients in understanding running speech when used in combination with lipreading compared with lipreading alone, and it also enabled them to understand some running speech when using electrical stimulation alone. An implantable receiver-stimulator and wearable speech processor embodying the principles of the prototype devices were then produced for clinical trial by the Australian biomedical firm, Nucleus Ltd, and its subsidiaries, Cochlear Pty Ltd and Cochlear Corporation. This cochlear implant was initially clinically trialled on six patients at The Royal Victorian Eye & Ear Hospital in 1982, and shown to give similar results to those obtained with the prototype device. In view of these findings a clinical trial was carried out for a Premarket Approval Application to the US Food and Drug Administration (FDA), and extended to a number of centres in the US, Canada, and West Germany. This clinical trial confirmed that patients could understand running speech when electrical stimulation was combined with lipreading, and that some patients could also understand running speech when using electrical stimulation alone. Today, more than 600 patients world-wide are using cochlear implants developed from the research described in this paper.