Graeme Clark Collection

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    Results in children using the 22 electrode cochlear implant [Abstract]
    Dawson, Pam W. ; Blamey, Peter J. ; Clark, Graeme M. ; Busby, P. A. ; Rowland, L.C. ; Dettman, S. J. ; Brown, A. M. ; Dowell, Richard C. ; Rickards, Field W. ; Alcantara, Joseph I. ( 1989)
    Abstract not available due to copyright.
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    Evaluation of a two-formant speech-processing strategy for a multichannel cochlear prosthesis
    Dowell, R. C. ; Seligman, P. M. ; Blamey, P. J. ; Clark, Graeme M. ( 1987)
    Initial results with the two-formant speech-processing strategy (F0FIF2) confirm the advantage of a multichannel cochlear prosthesis capable of stimulating at different sites within the cochlea. The successful presentation of two spectral components by varying the place of stimulation leads to the possibility of presenting further spectral information in this manner. Because virtually all multichannel implant patients demonstrate good "place" (electrode site) discrimination, these more refined coding strategies should lead to benefits for the majority of implantees. Already, with the F0FIF2 strategy, we have a system that appears to provide some effective auditory-alone communication ability for the average patient.
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    A multiple-electrode intracochlear implant for children
    Clark, Graeme M. ; Blamey, Peter J. ; Busby, Peter A. ; Dowell, Richard C. ; Franz, Burkhard K-H. ; Musgrave, Gaye Nicholls ; Nienhuys, Terry G. ; Pyman, Brian C. ; Roberts, Susan A. ; Tong, Yit C. ; Webb, Robert L. ; Kuzma, Januz A. ; Money, David K. ; Patrick, James F. ; Seligman, Peter M. ( 1987)
    A multiple-electrode intracochlear implant that provides 21 stimulus channels has been designed for use in young children. It is smaller than the adult version and has magnets to facilitate the attachment of the headset. It has been implanted in two children aged 5 and 10 years. The two children both lost hearing in their third year, when they were still learning language. Following implantation, it was possible to determine threshold and comfortable listening levels for each electrode pair. This was facilitated in the younger child by prior training in scaling visual and electrotactile stimuli. Both children are regular users of the implant, and a training and assessment program has been commenced.
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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.