Graeme Clark Collection
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ItemA multiple-channel cochlear implant: an evaluation using nonsense syllables( 1981)A study using nonsense syllables has shown that a multiple-channel cochlear implant with speech processor is effective in providing information about, voicing and manner and to a lesser extent place distinctions. These distinctions supplement lipreading cues. Furthermore, the average percentage improvements in overall identification scores for multiple-channel electrical stimulation and lipreading compared to lipreading alone were 71% for a laboratory-based speech processor and 122 % for a wearable unit.
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ItemClinical results for postlingually deaf patients implanted with multichannel cochlear prostheses( 1987)Clinical results for 24 patients using the Nucleus 22-channel cochlear prosthesis have shown the device to be successful in presenting amplitude, fundamental frequency, and second formant information to patients with acquired hearing loss. For all patients, this has meant a significant improvement in their communication ability when using lipreading and some ability to understand unknown speech without lipreading or contextual cues. Approximately 40% of patients are able to understand running speech in a limited fashion without lipreading, and this ability has been evaluated using the speech-tracking technique for a number of patients. Many patients are able to have limited conversations on the telephone without using a special code. Although the prosthesis has been designed with the presentation of speech signals in mind, recognition and discrimination of environmental sounds has also been very encouraging with patients scoring 70% to 80% correct for closed set environmental sound testing. Follow-up testing has indicated that the ability to understand open set speech without lipreading continues to improve up to at least 12 months postoperatively. Open set sentence test results improved from an average of 20% at 3 months to 40% at 12 months.
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ItemAcoustic parameters measured by a formant-estimating speech processor for a multiple-channel cochlear implant( 1987)Abstract not available due to copyright.
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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
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ItemA formant-estimating speech processor for cochlear implant patients(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.