Graeme Clark Collection

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    Factors affecting speech perception outcomes for older children using multichannel cochlear implants
    Dowell, Richard C. ; Dettman, Shani J. ; Hill, Katie ; Winton, Elizabeth ; Hollow, Rod ; Clark, Graeme M. ( 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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    Post-implant habilitation for children using cochlear implants: effects on long-term outcome
    Dowell, Richard C. ; Dettman, Shani J. ; WILLIAMS, SARAH ; TOMOV, ALEXANDRA ; Hollow, Rod ; Clark, Graeme M. ( 2002)
    Most clinicians working in the cochlear implant field advocate a regular habilitation program for young children receiving implants. The development of auditory skills and the incorporation of these skills into language development are thought to be key areas for such programs. Studies of speech perception and language outcomes demonstrate that an educational approach that emphasises spoken language development appears to enhance the results for implanted children. It remains difficult, however, to demonstrate clearly the effect of habilitation objectively and to determine how much individual attention is desirable for each child. This pilot study considered the long term speech perception and language outcomes for two groups of children who received Nucleus cochlear implants in Melbourne. One group (n=17) was identified as receiving regular habilitation from the Melbourne Cochlear Implant Clinic over a four year post-operative period. Another group (n=l1) was identified as receiving very little regular habilitation over the post-operative period. The language and speech perception results for these two groups showed a significant difference in performance on a wide range of measures with the group receiving regular formal habilitation demonstrating better performance on all measures. These groups included only congenitally, profoundly hearing-impaired children and did not differ significantly on mean age at implant or experience at the time of assessment. Further studies are needed to clarify these results on a larger group of children, and to control for additional confounding variables. Nonetheless, these preliminary results provide support for the incorporation of regular long-term habilitation into cochlear implant programs for children.
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    Predicting speech perception outcomes for children using multichannel cochlear implants [Abstract]
    Dowell, Richard C. ; Dettman, Shani J. ; WILLIAMS, SARAH ; Hill, Katie ; TOMOV, ALEXANDRA ; Clark, Graeme M. ( 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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    What factors contribute to successful outcomes for children using cochlear implants
    Cowan, Robert C. ; Clark, Graeme M. ; Dowell, Richard C. ; Dettman, Shani J ; Barker, Elizabeth ; Latus, Katie ; Hollow, Rod ; Blamey, Peter J. ( 2000)
    Long term speech perception data has been collected for 100 children using the Nucleus multichannel cochlear prosthesis in Melbourne. Scores on a number of different assessments are available at approximately six month intervals following implantation for these children. The group represents an unselected sample of cochlear implant users, as all children were included if they had sufficient developmental skills to perform formal speech perception tests. Information was also collected on each child regarding type of hearing loss, age of onset of profound hearing loss, duration of profound hearing loss, age at implantation, pre and post-implant communication mode, developmental delay, speech processing strategy and length of experience with implant use.
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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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    Application of the cochlear implant to profoundly hearing impaired adolescents: re-visiting the inclusion criterion for older children
    DETTMAN, SHANI ; Latus, Katie ; Cosson, Liz ; Dowell, Richard C. ; Clark, Graeme M. ( 2000)
    Objective: The purpose of this study is to examine the range of outcomes for older children receiving the multi-channel cochlear implant. Recent improvements in the speech perception performance for profoundly hearing impaired children and adults have lead to expanded selection criterion for cochlear implant inclusion. That is, the efficacy of cochlear implants for adults with acquired hearing loss is well documented. In addition, the application of the cochlear implant to young children has lead to improvements in open set speech perception, speech production and language acquisition. In contrast, congenitally deaf and prelingually deafened children who are implanted after the age of 8 years have performed poorer than children implanted at a younger age on speech perception, speech production and psychophysical performance measures.
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    Speech perception in noise with cochlear implant and hearing aid for implanted adolescents
    DETTMAN, SHANI ; Latus, Katie ; Cosson, Liz ; Dowell, Richard C. ; Clark, Graeme M. ( 2000)
    Objective. To describe the open set speech perception performance for 8 congenitally deaf adolescents who use a multichannel cochlear implant and behind-the ear hearing aid as their 'everyday listening' condition. Expanded indication for cochlear implant inclusion has lead to the implantation of a number of persons with severe to profound hearing loss. It has been suggested that persons who have some residual bearing are good candidates for the cochlear implant due to: the presence of more ganglion cells, prior auditory experience, pre-patterning of the auditory cortex or other factors, as yet unknown, such as language experience.
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    How much residual hearing is too much?
    Cowan, R. S. C. ; Dowell, R. C. ; Psarros, C. ; Dettman, S. J. ; Rance, G. ; Clark, Graeme M. ( 2000)
    The value of cochlear implants as an established clinical option for profoundly hearing-impaired adults and children has been supported by significant research results over a number of years (U.S. National Institutes of Health Consensus Statement 1995). As a direct consequence of the level of benefits shown for cochlear implant users on measures of speech perception, research has focused on investigating whether severely hearing impaired adults and children would be suitable candidates for cochlear implantation. I n considering the candidature of any individual, both medical and audiological suitability are investigated. The primary concern is to establish to what degree the patient would benefit from use of the cochlear implant.