Graeme Clark Collection
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ItemCognitive processing in children using cochlear implants: the relationship between visual memory, attention, and executive functions and developing language skills( 2002)We performed this study to determine whether children using a cochlear implant performed differently from age- and gender-matched hearing aid users on 8 neuropsychological measures of visual memory, attention, and executive functioning. The study also examined whether differences in cognitive skills could account for some of the observed variance in speech perception, vocabulary, and language abilities of hearing-impaired children. In contrast to previous studies, our results revealed no significant cognitive differences between children who use a cochlear implant and children who use hearing aids. Partial correlation analysis indicated that the children’s visual memory skills, i.e., their recognition memory, delayed recall, and paired associative learning memory skills, correlated significantly with their language skills. When examined at a significance level of .01, attention and executive functioning skills did not relate to the children’s developing speech perception, vocabulary, or language skills. The results suggested that differences in visual memory skills may account for some of the variance seen in the language abilities of children using implants and children using hearing aids.
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ItemSpeech perception outcomes in older children who use multichannel cochlear implants: Older is not always poorer(ANNALS PUBL CO, 2002-05)Speech perception outcomes for early-deafened children who undergo implantation as teenagers or young adults are generally reported to be poorer than results for young children. It is important to provide appropriate expectations when counseling adolescents and their families to help them make an informed choice regarding cochlear implant surgery. The considerable variation of results in this group makes this process more difficult. This study considered a number of factors in a group of 25 children who underwent implantation in Melbourne between the ages of 8 and 18 years. Each subject completed open-set speech perception testing with Bamford-Kowal-Bench sentences before and after implantation and preoperative language testing with the Peabody Picture Vocabulary Test. Data were collected regarding the type of hearing loss, age at implantation, age at hearing aid fitting, audiometric details, and preoperative and postoperative communication mode. Results were submitted to a stepwise multiple linear regression analysis with postoperative open-set sentence scores as the dependent variables. The analysis suggested that 3 factors have a significant predictive value for speech perception after implantation: preoperative open-set sentence score, duration of profound hearing loss, and equivalent language age. These 3 factors accounted for 66% of the variance in this group. The results of this study suggest that children who have useful speech perception before implantation, and higher age-equivalent scores on language measures, would be expected to do well with a cochlear implant. Consistent with other studies, a shorter duration of profound hearing loss is also advantageous. The mean sentence score for this group, 47%, was not significantly different from the mean result across all children in the Melbourne program.
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ItemSpeech perception in children using cochlear implants: prediction of long-term outcomes.(Informa UK Limited, 2002-03)A group of 102 children using the Nucleus multichannel cochlear implant were assessed for open-set speech perception abilities at six-monthly intervals following implant surgery. The group included a wide range of ages, types of hearing loss, ages at onset of hearing loss, experience with implant use and communication modes. Multivariate analysis indicated that a shorter duration of profound hearing loss, later onset of profound hearing loss, exclusively oral/aural communication and greater experience with the implant were associated with better open-set speech perception. Developmental delay was associated with poorer speech perception and the SPEAK signal coding scheme was shown to provide better speech perception performance than previous signal processors. Results indicated that postoperative speech perception outcomes could be predicted with an accuracy that is clinically useful.
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ItemSpeech perception outcomes for older patients using the nucleus cochlear implant [Abstract]( 2002)With improved medical technology and increased life expectancy, more patients are receiving cochlear implants at a later age. It is important to examine speech perception outcomes for older patients, in order to be able to provide appropriate pre-operative counselling regarding post-operative expectations. Speech perception scores for patients at the Melbourne Cochlear Implant Clinic implanted at age 65 or more were examined, and compared to the adult population implanted under the age of 65. (All of these patients were users of SPEAK or later strategies.) The aims were to see if speech perception scores were significantly different between the two groups as a whole, and to see if a correlation existed between increasing age of implantation above 65 and speech perception scores. Preliminary results suggest that there is a small but significant effect of age on speech perception outcomes. The findings from this study will be used to help clinicians provide more accurate advice and counselling for older patients, regarding the potential outcomes from a cochlear implant.
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ItemFactors affecting speech perception outcomes for older children using multichannel cochlear implants( 2002)Experience with cochlear implantation in early-deafened teenagers or young adults has been somewhat disappointing, however, in recent years a proportion of older children have demonstrated excellent speech perception performance. There appears to be a wide gap between the good and poor performers within this group. It is important to investigate the possible factors influencing performance so that adolescents and their families are able to make informed decisions regarding cochlear implant surgery. This study considered a number of factors in a group of 25 children implanted in Melbourne between the ages of 8 and 18 years. Each subject completed open set speech perception testing using BKB sentences before and after implantation and pre-operative language testing using the Peabody Picture Vocabulary Test. Data were collected regarding the type of hearing loss, age at implant, age at hearing aid fitting, audiometric details, and the pre-and postoperative communication mode. Multivariate analysis suggested that three factors have a significant predictive value for post-implant speech perception: pre-operative open-set sentence score, duration of profound hearing loss and equivalent language age. These three factors accounted for 66% of the variance in this group. The results of this study suggest that children who have useful pre-implant speech perception, and higher age-equivalent scores on language measures, would be expected to do well with a cochlear implant. A shorter duration of profound hearing loss is also advantageous. Mean speech perception scores for the older group were not significantly different from younger children.
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ItemPredicting speech perception outcomes for children using multichannel cochlear implants [Abstract]( 2002)The ability to predict outcomes for children who are cochlear implant candidates is most helpful in counselling families and making clinical recommendations. Open-set speech perception results have been collected for all children implanted with the Nucleus device in Melbourne. Speech perception as assessed at six month intervals following implantation. Information wascollected for each child regarding type of hearing loss, duration and age at onset of profound hearing loss, age at implantation, pre and post-implant communication mode, developmental delay, speech coding scheme and implant experience.
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ItemInitial speech perception results with the new multipeak speech processor for the 22-electrode cochlear prosthesis [Abstract]( [1990])A new speech processor has been developed for the 22-electrode cochlear prosthesis by Cochlear Pty Ltd working in conjunction with the Department of Otolaryngology at the University of Melbourne. The new device, known as the MSP, combines smaller, more efficient hardware with a new speech coding scheme in an attempt to provide better speech perception in everyday environments for implant users. The MSP operates with the current implant device so there is no need for existing implantees to have revision surgery to make use of the new development. The multipeak speech coding scheme, which has been implemented in the MSP, provides information from three high frequency spectral bands, in addition to the parameters of voice pitch, amplitude and first and second formants which have been provided in the existing FOFIF2 coding scheme for the last four years. Initial speech perception results with research subjects have shown significant improvements in performance for the MSP over the older system (WSP III). The most encouraging result is that open-set speech perception in the presence of competing noise has improved substantially. For example, mean scores for BKB sentences in a 10 dB signal-to-noise ratio were 64% for the MSP and 31% for the WSP III. Further investigations have shown that both the hardware improvements and the new multipeak speech coding scheme have contributed significantly to the overall improvement in performance. Studies are continuing to analyse further the potential of the new system.
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ItemMultiple-channel cochlear implants for children [Abstract]( [1991])The children's program at The University of Melbourne Cochlear Implant Clinic involves a team of ENT surgeons, audiologists, speech pathologists and a teacher of the deaf. After a child is considered suitable for implantation, he/she enters a preoperative program for a minimum of three months. During this time, there is counselling of parents, liaison with teachers, weekly training in speech production, language and speech perception and baseline assessments in these three areas. The child continues to receive weekly training and regular assessments in the postoperative period. Twenty children have been implanted in Melbourne with the 22-electrode cochlear implant to date. Formal results have been collected over time for nine of these children. Five children (aged 6.0 to 14.8 years at implantation) have known open-set speech recognition through hearing. Four of these five children were implanted before adolescence and the fifth, who had a deteriorating loss, was implanted during adolescence. The remaining children who did not demonstrate open-set recognition, were implanted during adolescence after a long duration of profound deafness. Postoperative performance on closed-set speech perception tests was better that preoperative performance for the group of five children with open-set recognition. There were also improvements in speech and language assessments.