Graeme Clark Collection

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    Speech perception in children using the advanced Speak speech-processing strategy
    Cowan, R. S. C. ; Brown, C. ; Whitford, L. A. ; Galvin, K. L. ; Sarant, J. Z. ; Barker, E. J. ; Shaw, S. ; King, A. ; Skok, M. ; Seligman, P. M. ; Dowell, R. C. ; Everingham, C. ; Gibson, W. P. R. ; Clark, Graeme M. ( 1995)
    The Speak speech-processing strategy, developed by the University of Melbourne and commercialized by Cochlear Pty Limited for use in the new Spectra 22 speech processor, has been shown to provide improved speech perception for adults in both quiet and noisy situations. The present study evaluated the ability of children experienced in the use of the Multipeak (Mpeak) speech-processing strategy (implemented in the Nucleus Minisystem-22 cochlear implant) to adapt to and benefit from the advanced Speak speech-processing strategy (implemented in the Nucleus Spectra 22 speech processor). Twelve children were assessed using Mpeak and Speak over a period of 8 months. All of the children had over 1 year's previous experience with Mpeak, and all were able to score significantly on open-set word and sentence tests using the cochlear implant alone. Children were assessed with both live-voice and recorded speech materials, including Consonant-Nucleus-Consonant monosyllabic words and Speech Intelligibility Test sentences. Assessments were made in both quiet and in noise. Assessments were made at 3-week intervals to investigate the ability of the children to adapt to the new speech-processing strategy. For most of the children, a significant advantage was evident when using the Speak strategy as compared with Mpeak. For 4 of the children, there was no decrement in speech perception scores immediately following fitting with Speak. Eight of the children showed a small (10% to 20%) decrement in speech perception scores for between 3 and 6 weeks following the changeover to Speak. After 24 weeks' experience with Speak, 11 of the children had shown a steady increase in speech perception scores, with final Speak scores higher than for Mpeak. Only 1 child showed a significant decrement in speech perception with Speak, which did not recover to original Mpeak levels.
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    Comparison of current speech coding strategies
    Whitford, L. A. ; Seligman, P. M. ; Blamey, Peter J. ; McDermott, H. J. ; Patrick, J. F. ( 1993)
    This paper reports on two studies carried out at the University of Melbourne jointly with Cochlear Pty Ltd. The studies demonstrated substantial speech perception improvements over the current Multipeak strategy in background noise.
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    Cochlear implants: high rate stimulation studies and the effect of electrode position [Abstract]
    Shepherd, R. K. ; Huang, C. Q. ; Xu, J. ; Tykocinski, M. ; Seligman, P. M. ; Clark, Graeme M. ( 1996)
    This paper summarizes our recent findings investigating the safety of high rate electrical stimulation, and reviews the effects of electrode position on auditory excitability. These studies used charge balanced biphasic pulses and electrode shorting between stimuli to minimize any residual charge or direct current. High rate (400-1000 pulses/s) electrical stimulation of the auditory nerve can result in significant stimulus induced reductions in auditory nerve excitability at stimulus levels well above those used clinically (1). The extent of this reduction was dependent on stimulus rate, intensity and duty cycle, implying that such changes were related to the degree of evoked activity.
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    Speech perception results for children changing from multipeak to SPEAK speech processing strategy [Abstract]
    Sarant, J.Z. ; DelDot, J. ; Dettman, S. ; Hollow, R. ; Skok, M. ; Seligman, P.M. ; Dowell, R.C. ; Gibson, W.P.R. ; Clark, Graeme M. ; Cowan, R. S. C. ; Pyman, B. ; Galvin, K. L. ; Shaw, S. ; Barker, E. J. ; Brown, C. ( 1996)
    In mid-1994, a new speech processing strategy termed SPEAK was introduced for the Nucleus Spectra-22 cochlear prostheses. To compare benefits in implanted children changing to the SPEAK strategy, speech perception in a group of twelve children from Melbourne and Sydney was evaluated. The children were assessed in quiet and in background noise.