Graeme Clark Collection

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    Initial results for six patients with a multiple-channel cochlear prosthesis
    Dowell, R. C. ; Brown, A. M. ; Seligman, P. M. ; Clark, Graeme M. (Monash University Press, 1983)
    A total of eight patients have been assessed with the multi-channel cochlear prosthesis at the University of Melbourne. The first two patients were implanted with a prototype device in 1978 and 1979, and their results with various speech evaluation procedures have been reported and summarized in detail elsewhere (Clark & Tong, 1982). Briefly, these results indicated that some very significant benefit could be obtained for these patients when using the cochlear prosthesis with external speech processing, particularly when using the device in conjunction with lipreading. It was also shown that some significant understanding of speech was possible without lipreading (open-set) for both patients, although this was fairly limited.
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    Speech perception of hearing aid users versus cochlear implantees
    Flynn, Mark C. ; Dowell, Richard, C. ; Clark, Graeme M. (Monduzzi Editore, 1997)
    Recent improvements in speech recognition abilities for profoundly deaf cochlear implantees suggests that some adults with a severe hearing impairment might benefit from a cochlear implant. Unfortunately, no studies have directly compared the speech perception abilities of the severely hearing impaired with those of cochlear implant users. An investigation of the speech perception performance of people with a severe hearing loss, who use hearing aids, was conducted in the Department of Otolaryngology at The University of Melbourne. Each participant (n=35) took part in a series of speech perception tests which included 11 vowel recognition tests, CNC words, CUNY sentences, and the Connected Speech Test. The results from these severely hearing impaired persons were compared to results from cochlear implant users. The group of severely hearing impaired adults performed better on tests of vowel and word perception but poorer on tests of open set sentence perception in comparison to a group of cochlear implant users.
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    Speech perception in implanted children: effects of speech processing strategy and residual hearing
    Meskin, T. ; Rance, G. ; Cody, K. ; Sarant, J. ; Larratt, M. ; Latus, K. ; Hollow, R. ; Rehn, C. ; Dowell, R.C. ; Pyman, B. ; Gibson, W.P.R. ; Clark, Graeme M. ; Cowan, Robert S. C. ; Barker, E. J. ; Pegg, P. ; Dettman, S. ; Rennie, M. ; Galvin, K. (Mendoza Editor, 1997)
    The ability of implanted children to adapt to different speech processing strategies has been demonstrated for the Nucleus implant system. Children previously experienced with the Multipeak speech processing strategy. were able to gain significant improvements in consonant, word and sentence perception using the Speak speech processing strategy. suggesting some degree of neural plasticity in neural-auditory coding. Of 192 implanted children with different degrees of preoperative residual hearing, 65% were found to obtain significant scores on open-set speech materials using electrical stimulation alone. Those children with more residual hearing had a greater probability of achieving open-set understanding and at a minimum level, perceived high frequency consonant information which would not have been available through conventional hearing aids.
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    Habilitation issues in the management of children using the cochlear multiple-channel cochlear prosthesis
    Galvin Karyn L. ; Dawson Pam W. ; Hollow Rod. ; Dowell Richard C. ; Pyman B. ; Clark Graeme, M. ; Cowan, Robert S. C. ; Barker, Elizabeth J. ; Dettman, Shani J. ; Blamey, Peter J. ; RANCE, GARY ; Zarant, Julia Z. ( 1993)
    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-impairment, a wide-range or 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 or 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 or 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 selling will have a bearing on the Integration of listening and device use Into the classroom environment.
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    Signal processing in quiet and noise
    Dowell, R. C. ; Patrick, J. F. ; Blamey, P. J. ; Seligman, P. M. ; Money, D. K. ; Clark, Graeme M. ( 1987)
    It has been shown that many profoundly deaf patients using multichannel cochlear implants are able to understand significant amounts of conversational speech using the prosthesis without the aid of lipreading. These results are usually obtained under ideal acoustic conditions but, unfortunately, the environments in which the prostheses are most often used are rarely perfect. Some form of competing signal is always present in the urban setting, from other conversations, radio and television, appliances, traffic noise and so on. As might be expected, implant users in general find background noise to be the largest detrimental factor in their understanding of speech, both with and without the aid of lipreading. Recently, some assessment of implant patient performance with competing noise has been attempted using a four-alternative forced-choice spondee test (1) at Iowa University. Similar testing has been carried out at the University of Melbourne with a group of patients using the Nucleus multichannel cochlear prosthesis. This study formed part of an assessment of a two formant (F0/FI/F2) speech coding strategy (2). Results suggested that the new scheme provided improved speech recognition both in quiet and with competing noise. This paper reports on some more detailed investigations into the effects of background noise on speech recognition for multichannel cochlear implant users.
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    A formant-estimating speech processor for cochlear implant patients
    Blamey, P. J. ; Dowell, R. C. ; Brown, A. M. ; Seligman, P. M. ; Clark, Graeme M. (Speech Science and Technology Conference, 1986)
    A simple formant-estimating speech processor has been developed to make use of the "hearing" produced by electrical stimulation of the auditory nerve with a multiple-channel cochlear implant. Thirteen implant patients were trained and evaluated with a processor that presented the second formant frequency, fundamental frequency, and amplitude envelope of the speech. Nine patients were trained and evaluated with a processor that presented the first formant frequency and amplitude as well. The second group performed significantly better in discrimination tasks and word and sentence recognition through hearing alone. The second group also showed a significantly greater improvement when hearing and lipreading was compared with lipreading alone in a speech tracking task.