Graeme Clark Collection

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Author: Blamey, Peter × End date: 1989 × Start date: 1980 × Subject: cochlear implant × Subject: otolaryngology ×

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Now showing 1 - 9 of 9
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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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    Two-component hearing sensations produced by two-electrode stimulation in the cochlear of a deaf patient
    Tong, Y. C. ; Dowell, R. C. ; Blamey, P. J. ; Clark, Graeme M. ( 1983)
    http://www.sciencemag.org/cgi/content/abstract/219/4587/993?ijkey=v6jEOhdpzPCxw&keytype=ref&siteid=sci
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    Psychophysical studies evaluating the feasibility of a speech processing strategy for a multiple-channel cochlear implant
    Tong, Y. C. ; Blamey, P. J. ; Dowell, R. C. ; Clark, Graeme M. ( 1983)
    Abstract not available due to copyright.
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    Psychophysical matching of sensations produced by acoustic and electrical stimulation of the auditory nerve [Abstract]
    Blamey, P. J. ; Dowell, R. C. ; Tong, Y.C. ; Clark, Graeme M. (Monash University Press, 1983)
    The aim of this study was to establish an acoustic model of a multiple-channel cochlear implant that could be used in the development of speech coding strategies. Identical psychophysical tests were carried out with electrical stimuli for two cochlear implant patients and with acoustic stimuli for three normally hearing listeners. Each electrical stimulus was a train of biphasic pulses at a constant rate between 50 and 100 pps directed to one of the 10 electrodes spaced at 1.5mm intervals around the basal turn of the cochlea (Clark et al. 1977). The corresponding acoustic stimulus was a train of noise bursts at a rate equal to the electrical pulse rate. The noise bursts were passed through one of 8 bandpass filters with centre frequencies equally spaced on a logarithmic scale from 1140 to 10880 Hz representing 8 different electrodes.
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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.
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    A model of auditory-visual speech perception
    Blamey, P. J. ; Clark, Graeme M. (Speech Science and Technology Conference, 1986)
    A mathematical model relating the probabilities of correctly recognizing speech features, phonemes, and words was tested using data from the clinical trial of a multiple-channel cochlear implant. A monosyllabic word test was presented to the patients in the conditions hearing alone (H), lipreading alone (L), and hearing plus lipreading (HL). The model described the data quite well in each condition. The model was extended to predict the HL scores from the feature recognition probabilities in the H and L conditions. The model may be useful for the evaluation of automatic speech recognition devices as well as hearing impaired people.