Graeme Clark Collection

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    Speech perception outcomes in older children who use multichannel cochlear implants: Older is not always poorer
    Dowell, RC ; Dettman, SJ ; Hill, K ; Winton, E ; Barker, EJ ; Clark, GM (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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    Speech perception in children using cochlear implants: prediction of long-term outcomes.
    Dowell, RC ; Dettman, SJ ; Blamey, PJ ; Barker, EJ ; Clark, GM (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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    Speech perception in implanted children: influence of preoperative residual hearing on outcomes [Abstract]
    Cowan, R. S. C. ; Barker, E. J. ; Pegg, P. ; Dettman, S. ; Rennie, M. ; Galvin, K. ; Meskin, T. ; Rance, G. ; Cody, K. ; Sarant, J. ; Larratt, M. ; Latus, K. ; HOLLOW, RODNEY ; Rehn, C. ; Dowell, R. C. ; Pyman, B. ; Gibson, W. P. R. ; Clark, Graeme M. ( 1998)
    Since the first child was implanted with the Nucleus 22-channel prosthesis in Melbourne in 1985, several thousand children world-wide have now benefitted from this technology. More effective paediatric assessment and management procedures have now been developed, allowing cochlear implants to be offered to children under the age of 2 years. Improvements in speech processing strategy have also been implemented in the Nucleus implant system, resulting in increased mean speech perception benefits for implanted adults. Although a range of performance on formal measures of hearing, speech or language has been reported for children using implants, results from the first decade of implant experience consistently show that significant benefits are available to children receiving their implant at an early age. Reported speech perception results for implanted children show that a considerable proportion (60%) of paediatric patients in the Melbourne and Sydney clinics are able to understand some open-set speech using electrical stimulation alone. These results, and the upward trend of mean speech perception benefits shown for postlinguistically deafened adults have raised questions as to whether severely, or severely-to-profoundly deaf children currently using hearing aids would in fact benefit more from a cochlear implant. To investigate the potential influence of the degree of preoperative residual hearing on postoperative speech perception, results for all implanted children in the Melbourne and Sydney cochlear implant programs were analysed. Results showed that as a group, children with higher levels of preoperative residual hearing were consistently more likely to achieve open-set speech perception benefits. Potential factors in this finding could be higher levels of ganglion cell survival or greater patterning of the auditory pathways using conventional hearing aids prior to implantation. Conversely, children with the least preoperative residual hearing were less predictable, with some children achieving open-set perception, and others showing more limited closed-set benefits to perception. For these children, it is likely that preoperative residual hearing is of less significance than other factors in outcomes.
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    Latest results for adults & children using cochlear implants & future implications
    Cowan, Robert C. ; Clark, Graeme M. ; Dowell, Richard C. ; Dettman, Shani J ; Barker, Elizabeth ; Latus, Katie ; Hollow, Rod ; Blamey, Peter J. ( 2000)
    The overall success of a cochlear implant procedure is most often quantified by assessing how well implantees can understand speech. This is because a primary aim of the application of cochlear implants is to improve communication, and it is relatively straightforward to obtain accurate measures of speech recognition. The quality of cochlear implant hearing is not well described by measuring an audiogram, as the detection of sound is similar across all implantees if the device is functioning correctly. A commonly used measure of speech understanding is the CID everyday sentence test where the number of correctly identified words within sentences is assessed. In the early days of cochlear implants, subjects could only recognize a few words without lipreading but the most recent results show average scores of 80% without lipreading for this sentence test, after 6 months of experience with the device.
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    Speech perception in implanted children: effects of speech processing strategy and residual hearing
    Meskin, T. ; Rance, G. ; Cody, K. ; Sarant, J. ; Larratt, M. ; Latus, K. ; Hollow, R. ; Rehn, C. ; Dowell, R.C. ; Pyman, B. ; Gibson, W.P.R. ; Clark, Graeme M. ; Cowan, Robert S. C. ; Barker, E. J. ; Pegg, P. ; Dettman, S. ; Rennie, M. ; Galvin, K. (Mendoza Editor, 1997)
    The ability of implanted children to adapt to different speech processing strategies has been demonstrated for the Nucleus implant system. Children previously experienced with the Multipeak speech processing strategy. were able to gain significant improvements in consonant, word and sentence perception using the Speak speech processing strategy. suggesting some degree of neural plasticity in neural-auditory coding. Of 192 implanted children with different degrees of preoperative residual hearing, 65% were found to obtain significant scores on open-set speech materials using electrical stimulation alone. Those children with more residual hearing had a greater probability of achieving open-set understanding and at a minimum level, perceived high frequency consonant information which would not have been available through conventional hearing aids.
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    Speech perception in implanted children: effects of preoperative residual hearing and speech processing strategy [Abstract]
    Meskin, T. ; Rance, G. ; Cody, K. ; Sarant, J. ; Larratt, M. ; Latus, K. ; HOLLOW, RODNEY ; Rehn, C. ; Dowell, R.C. ; Pyman, B. ; Gibson, W.P.R. ; Clark, Graeme M. ; Cowan, Robert S. C. ; Barker, E. J. ; Pegg, P. ; Dettman, S. ; Rennie, M. ; Galvin, K. ( 1997)
    Since the first child was implanted with the Nucleus 22-channel cochlear prosthesis in Melbourne in 1985, the number of implanted children world-wide has rapidly expanded. Over this period, more effective paediatric assessment and management procedures have developed, allowing cochlear implants to be offered to children under the age of 2 years. In addition, a succession of improved speech processing strategies have been implemented in the Nucleus implant system, resulting in increased mean speech perception benefits for implanted adults. Research in the Melbourne and Sydney Cochlear Implant Clinics has also demonstrated that young children can adapt to and benefit from improved speech processing strategies such as the Speak strategy. Reported speech perception results for implanted children show that a considerable proportion (60%) of paediatric patients in the Melbourne and Sydney clinics are able to understand some open set speech using electrical stimulation alone. These results, and the upward trend of speech perception benefits to improve over time with advances in speech processing. have raised questions as to whether severely, or severely-to-profoundly deaf children currently using hearing aids would in fact benefit more from a cochlear implant. To investigate the potential effect of the level of preoperative residual hearing on postoperative speech perception. results for all implanted children in the Melbourne and Sydney cochlear implant programs were analysed. Results showed that as 8 group, children with higher levels of preoperative residual hearing were consistently more likely to achieve open-set speech perception benefits. Potential factors in this finding could be higher levels of ganglion cell survival or greater patterning of the auditory pathways using conventional hearing aids prior to implantation. Conversely, children with the least preoperative residual hearing were less predictable, with some children achieving open-set perception, and others showing more limited closed-set benefits to perception. For these children, it is likely that preoperative residual hearing is of less significance than other factors in outcomes.