Graeme Clark Collection
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ItemResults of multiple-electrode cochlear implants in children( 1987)Children in Australia and United States of America are now being implanted with the Nucleus 22 electrode intracochlear prosthesis utilizing the F0/F1F2 coding strategy. A total of 32 adolescents (10-17 years) and 24 preadolescents (2-9 years) have been implanted as of 31 August, 1987. No significant postoperative complications were recorded, the speech processors were successfully programmed, and all are users of the device. For the 56 children, the average length of postoperative stimulation time is 2.8 months. Because the majority of children have such short experience with the device we report herein two children from the University of Melbourne (A) and two children from the United States (U) who have been using the Nucleus system for 12 months or more. Child 1A has only 10 electrodes in the cochlea; therefore, the number of channels programmed for the children is 10, 17, 18 and 18, respectively. Child Al and A2 were deafened by meningitis at 3-3 and 3 years of age, respectively. Child U3 became profoundly deafened from a progressive sensorineural loss at age 11 and Child U4 was deafened by recurrent cochlear hydrops at age 13 years.
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ItemSignal processing in quiet and noise( 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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ItemThe histopathology of the human temporal bone following cochlear implantation in a patient: a summary( 1987)The macroscopic and microscopic evaluation of the implanted and unimplanted temporal bones in a patient who had a cochlear prosthesis for 27 months prior to his death from cardiac disease has shown that the device is biocompatible, and does not lead to any significant adverse effects. The cause of deafness was meningitis.
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ItemSpeech recognition abilities in profoundly deafened adults using the Nucleus 22 Channel Cochlear Implant System( 1987)Research in the area of cochlear prostheses to restore a level of hearing sensation to the profoundly deaf has been ongoing at a number of centers throughout the world since the 1960's. 3, 4, 7, 8,. Work on a multichannel cochlear implant that utilizes a speech feature extraction coding strategy and multi-sited, sequential, bipolar stimulation to enhance pitch perception began at the University of Melbourne under the direction of Professor Graeme Clark in the 1970's. Collaboration with Nucleus Limited, a multi-national biomedical corporation from Australia, led to the development of the current version of the prosthesis. The Nucleus 22 Channel Cochlear Implant System has been described in detail elsewhere. 1, 5