Graeme Clark Collection

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    Predicting speech perception results for children using multichannel cochlear implants [Abstract]
    Dowell, Richard C. ; Dettman, Shani J. ; WILLIAMS, SARAH ; Hill, Katie ; TOMOV, ALEXANDRA ; Clark, Graeme M. ( 2002)
    It is most helpful in counselling families considering cochlear implantation to have some ability to predict outcomes for individual hearing-impaired children. Speech perception results for open-set words and sentences have been collected for all children implanted with the Nucleus device in Melbourne. Assessments are available at approximately six month intervals following implantation, Data was collected 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. These data were used as predictor variables in step-wise multiple linear regression analyses with the speech perception scores as the dependent variables. Shorter duration of profound hearing loss, later onset of profound hearing loss, exclusively oral communication mode following implantation, and longer implant experience were associated with significantly (p < 0.00 I) improved open-set speech perception. The use of the SPEAK signal coding scheme was shown to provide significantly better speech perception performance for children (p < 0.00 I). Developmental delay was associated with poorer speech perception outcomes (p < 0.0 I). Over 50% of the variance in speech perception scores was accounted for by these variables. The study suggests that younger implantation for congenitally deaf children leads to improved speech perception results. On the other hand, the development of auditory language skills in implanted children may be as important as age at implantation in enhancing long term outcomes. Regression equations derived from these results can be used to predict outcomes for cochlear implant candidates with a reasonable accuracy.
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    Variation in speech perception scores among children with cochlear implants
    Sarant, JZ ; Blamey, PJ ; Dowell, RC ; Clark, GM ; Gibson, WPR (LIPPINCOTT WILLIAMS & WILKINS, 2001-02)
    OBJECTIVE: The objective of this study was to identify common factors affecting speech perception scores in children with cochlear implants. DESIGN: Speech perception data for 167 implanted children were collected at two cochlear implant centres in Melbourne and Sydney. The data comprised audition-alone scores on open-set word and sentence tests. Children were selected on the basis that they had a Nucleus 22-electrode cochlear implant. The average age of the children was 5 yr. Information was also collected about 12 factors that may have influenced speech perception scores for each child. Analysis of covariance was used to identify factors that significantly affected speech perception scores. Pearson pairwise correlation coefficients were also calculated for all factors analyzed. RESULTS: The analyses in this study identified factors that accounted for 51%, 34%, and 45% of the variance in phoneme, word and sentence perception scores. Scores decreased by 1.4 to 2.4% per year of profound deafness prior to implantation. Children who normally use oral communication scored significantly higher than children normally using sign or simultaneous oral and sign communication. Children implanted in Sydney scored higher on average than children implanted in Melbourne. CONCLUSIONS: The results show that a significant part of the variation in speech perception scores is systematically related to audiological and environmental factors for each child. The reasons for significant differences between children using different communication modes or from different clinics were not identified.
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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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    Pre-operative hearing assessment in young cochlear implant candidates
    RANCE, GARY ; Dowell, Richard C. ; Rickards, Field W. ; Clark, Graeme M. ( 2000)
    Early implantation of congenitally deaf candidates is now a goal of most cochlear implant clinics. This objective can only be achieved through the use of audiological tests that are able to identify and quantify hearing loss in infancy. Behavioural conditioning techniques provide the most accurate indication of hearing acuity in older subjects, but these procedures are unreliable in young (6 months) or developmentally delayed children. This paper investigates the degree of accuracy with which two electrophysiological test techniques (click-ABR & steady-state evoked potential [SSEPD can be used to assess auditory function in infants with significant hearing loss. ABR and SSEP findings from 108 children were compared with hearing levels obtained behaviourally.
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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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    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.