Graeme Clark Collection
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ItemMultichannel auditory brainstem implants: an Australian case study [Abstract]( 1996)The multichannel Auditory Brainstem Implant (ABI) is an implantable device designed to restore a level of auditory perception in patients with bilateral acoustic neuromas, where the removal of the tumours is expected to result in a total loss of hearing. As with the cochlear implant, the ABI utilises an externally worn speech processor and headset, together with a surgically-placed receiver-stimulator and electrode array. The electrode array, developed through the collaboration of the House Ear Institute in the United States and Cochlear Corporation, consists of eight electrodes on a carrier, which is placed on the surface of the brainstem in the area of the cochlear nucleus.
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ItemCurrent trends in speech perception performance in adult cochlear implant patients [Abstract]( 1996)In 1994, Cochlear Pty. Ltd. (Now Cochlear Limited) released a new speech processor, the Spectra 22, for use with the Nucleus 22-channel cochlear implant. The Spectra 22 speech processor incorporates a new speech processing strategy called SPEAK, which is based upon research conducted by the University of Melbourne. This paper reports post-operative scores on open-set word and sentence materials for adult patients in the Melbourne Cochlear Implant Clinic who have been started up with the Spectra 22 speech processor.
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ItemSpeech perception in people with a severe hearing loss: preliminary results [Abstract]( 1996)Recent improvements in multichannel cochlear implants have led to improved speech perception for people with profound hearing impairments. Given this improvement, it has been suggested that some people with severe hearing impairments would be more successful with a cochlear implant than a hearing aid. Unfortunately little research exists to support the suitability of cochlear implants for these individuals. In order to determine this, a detailed investigation of the aided performance of people with severe hearing losses is being conducted at The University of Melbourne (School of Audiology). Severe hearing loss was defined as a pure tone average of greater than 60dBHL, but no worse that 100dBSPL in the better ear. At present, 15 participants have taken part in this study and their results will be discussed. Each participant took part in a standard audiometric assessment which included an audiogram, AB words, tympanometry with acoustic reflexes and an ABR. Each participant’s hearing aids were assessed to make sure that they were optimally aided. Following the hearing aid evaluation the participants took part in a series of traditional speech perception tests which included 24 consonant recognition, 11 vowel recognition, CNC words, CUNY sentences, and the Connected Speech Test (CSTv2). Other tests of speech perception were conducted which looked at the effects of different types of background noise, amounts of reverberation, rates of speech and amount of available context. The aim of this was to better simulate “real-life” listening conditions. Consequently, a range of results for both traditional assessments of speech perception and simulated listening conditions will be presented and compared.
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ItemSpeech perception for hearing aid users versus cochlear implantees [Abstract]( 1996)Abstract not available due to copyright.
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ItemSpeech perception for children with different levels of residual hearing using the cochlear 22-channel cochlear prosthesis [Abstract[( 1996)Over the past 10 years, since the implantation of the first children with the Nucleus 22-channel cochlear prosthesis in Melbourne, the number of profoundly deaf children using this implant system has rapidly expanded. Longer-term experience with implanted children has led to improvements in paediatric assessment and management. Speech processing strategies have also been improved, resulting in a series of increases in speech perception benefits. Results of comparative studies of Speak and Multipeak speech processing strategies have shown that open-set word and sentence scores for a group of thirteen children evaluated over a two year period showed an advantage with the Speak speech processing strategy. The increases were noted particularly in speech perception in poor signal-to-noise conditions. Analysis has shown that consonant perception was significantly increased, due to an improved place perception. Given current speech perception scores for implanted children, it has been suggested that severely-to-profoundly deaf children currently using hearing aids could in fact benefit more from a cochlear implant. Preliminary investigation of results for children in the Melbourne and Sydney cochlear implant programs has shown that children with higher levels of preoperative residual hearing as a group do score significantly on open-set word and sentence perception tests using the implant alone. In children with lower levels of residual hearing, results were variable across the group.
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ItemVowel imitation task: results over time for 28 cochlear implant children under the age of eight years( 1995)With increasing numbers of implanted children under the age of 4 years, numerous researchers have reminded us of the need for valid, sensitive, and reliable tests of developing speech perception.1,2 In addition to studies of the efficacy of implanted prostheses, there is a need to investigate the many variables that influence children's communicative performance, such as changes in speech-coding strategy, updated speech-processing systems, the effects of various training regimens, and the selection of educational and communication modes.
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ItemSpeech perception, production and language results in a group of children using the 22-electrode cochlear implant( 1992)Five children out of a group of nine (aged 5.5 to 19.9 years) implanted with the 22-electrode cochlear implant (Cochlear Ply. Ltd.) have achieved substantial scores on open-set speech tests using hearing without lipreading. Phoneme scores for monosyllabic words ranged from 40% to 72%. Word scores in sentences ranged from 26% to 74%. Four of these five children were implanted during preadolescence. The fifth child, who had a progressive loss and was implanted during adolescence after a short period of very profound deafness, scored highest on all speech perception tests. The remaining four children who did not demonstrate open-set recognition were implanted during adolescence after a long duration of profound deafness. Post-operative performance on closed-set speech perception tests was better than pre-operative performance for all children. Improvements in speech and language assessments were also noted. These improvements tended to be greater for the younger children. The results are discussed with reference to variables which may contribute to successful implant use: such as age at onset, duration of profound hearing loss, age at implantation, aetiology, educational program, and the type of training provided.
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ItemInitial results for six patients with a multiple-channel cochlear prosthesis(Monash University Press, 1983)A total of eight patients have been assessed with the multi-channel cochlear prosthesis at the University of Melbourne. The first two patients were implanted with a prototype device in 1978 and 1979, and their results with various speech evaluation procedures have been reported and summarized in detail elsewhere (Clark & Tong, 1982). Briefly, these results indicated that some very significant benefit could be obtained for these patients when using the cochlear prosthesis with external speech processing, particularly when using the device in conjunction with lipreading. It was also shown that some significant understanding of speech was possible without lipreading (open-set) for both patients, although this was fairly limited.
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ItemRehabilitation strategies for adult cochlear implant users(Monduzzi Editore, 1997)This paper summarizes open-set speech perception results using audition alone for a large group of adult Nucleus cochlear implant users in Melbourne. The results show wide variation in performance but significant improvement over the years from 1982 to 1995. Analysis of these results shows that speech processor developments have made the major contribution to this improvement over this time. Recent results for patients using the SPECTRA-SPEAK processor show !hat most subjects obtain good speech perception within six months of implantation and the need for intensive auditory training is minimal for many of these patients. Postoperative care should encourage consistent device use by providing opportunities for success and providing long term technical support for implant users. In some cases, including elderly patients, those with long term profound deafness, and those with special needs, there will still be a need for additional rehabilitation and auditory training support.
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ItemFactors affecting outcomes in children with cochlear implants(Monduzzi Editore, 1997)Open-set speech perception tests were completed for a group of 52 children and adolescents who were long-term users of the Nucleus multiple channel cochlear prosthesis. Results showed mean scores for the group of 32.4% for open-set BKE sentences and 48.1% for phonemes in open-set monosyllabic words. Over 80% of the group performed significantly on these tas1cs. Age at implantation was identified as a significant factor affecting speech perception performance with improved scores for children implanted early. This factor was evident in the results at least down to the age of three years. Duration.. of profound hearing loss, progressive hearing loss, educational program and preoperative residual hearing were also identified as significant factors that may affect speech perception performance.