Graeme Clark Collection
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ItemPsychophysical studies on cochlear implant patients deafened prior to 4 years of age [Abstract]( 1989)Abstract not available due to copyright.
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ItemResults for two children using a multiple-electrode intracochlear implant( 1989)Abstract not available due to copyright.
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ItemThe University of Melbourne/Nucleus cochlear prosthesis( 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.
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ItemSpeech perception with cochlear implants and tactile aids [Abstract]( 1988)Abstract not available due to copyright.
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ItemThe engineering of future cochlear implants(Croom Helm, 1985)Speech is a complex acoustic signal, and information is transmitted to the brain at a rapid rate. For example during a conversation ten phonemes are uttered per second. Furthermore, these complex speech sounds are coded into patterns of neural discharges that enable the subject to understand speech. In order, therefore, to bring speech signals directly to residual auditory nerve fibres, considerable processing of the speech signal is required before the central nervous system will recognise and comprehend it. The magnitude of the task can be further appreciated when one considers that there are an average of 31,400 nerve fibres in the human auditory nerve and a large proportion of these convey information to the brain about the speech frequencies. Research studies are showing, however, that the perception of ongoing speech with cochlear implants may be achieved 'With speech processing strategies which can be achieved by current electronic technology.
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ItemTelephone use by a multi-channel cochlear implant patient: an evaluation using open-set CID sentences(Cambridge University Press, 1985)A totally deaf person with a multiple-channel cochlear prosthesis obtained open-set speech discrimination using the telephone. CID Everyday Sentences were presented by telephone to the patient, who repeated an average of 21 per cent of key words correctly on the first presentation, and 47 per cent when a repeat of the sentences was permitted. This result is consistent with the patient's reports of telephone usage.
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ItemA comparison of three speech coding strategies using an acoustic model of a cochlear implant( 1985)Abstract not available due to copyright.
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ItemCochlear implant and otitis media: a pilot study to assess the feasibility of pseudomonas aeruginosa and streptococcus pneumoniae infection in the cat( 1984/85)An experimental model for the induction of otitis media in cats is described using pseudomonas aeruginosa and streptococcus pneumoniae. Until now the cat has been regarded as being resistant to streptococcus pneumoniae infections, whereas pseudomonas aeruginosa is known to cause a most virulent otitis media in this animal. A successful inoculation using streptococcus pneumoniae, however, can be achieved by direct inoculation of a highly concentrated suspension of microorganisms in the bulla, retention of the organisms by Gelfoam®, and enhancement of virulence by intrapertioneal inoculation in mice. The model promises to be an important contribution in studying the effects of pneumococcal otitis media in Cochlear Implants.
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ItemComparison of two cochlear implant speech-processing strategies( 1984)Speech processors extracting either the fundamental frequency (F0) alone, or the fundamental frequency combined with second formant information (F0-F2), have been evaluated on a totally deaf patient using a multiple-channel cochlear implant. A closed set test using 16 spondees and a modified rhyme test showed that for electrical stimulation alone the F0-F2 speech processor was significantly better than the F0 processor. The open set tests using phonetically balanced words and Central Institute for the Deaf everyday sentences showed that for electrical stimulation alone and electrical stimulation combined with lipreading, the results with the F0-F2 speech processor were all significantly better than with the F0 processor. Information transmission for consonant speech features was also better when using the F0-F2 processor.
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ItemSurgery for an improved multiple-channel cochlear implant( 1984)An improved multiple-channel cochlear implant has been developed. The titanium container with enclosed electronics, the receiver coil and the connector are embedded in medical-grade Silastic. The upper half of the implant has a diameter of 35 mm and a height of 4.5 mm. and the lower half a diameter of 23 mm and a height of.5 mm. The electrode array has also been designed to reduce the possibility of breakage due to repeated movements over many years. The surgery involves drilling a bed in the mastoid bone for the receiver-stimulator, and fixing the proximal electrode under the mastoid cortex. Gentle insertion of the electrode array through the round window and along the seala tympani is achieved with a specially designed microclaw.