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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    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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    The development of speech perception in children using cochlear implants: effects of etiologic factors and delayed milestones
    PYMAN, BRIAN ; Blamey, Peter J. ; Lacy, Peter ; Clark, Graeme M. ; DOWELL, RICHARD ( 2000)
    Hypothesis: Speech perception outcomes for cochlear implantation of children vary over a wide range, and it is hypothesized that central pathologic states associated with certain causes of hearing impairment account for a substantial part of the variance. Study Design: A retrospective analysis was carried out to ascertain the relationships between speech perception, etiologic factors, and central pathologic states as indicated by preoperative delayed motor milestones and/or cognitive delays. Setting: Data were obtained from the pre-and postoperative records of patients attending a hospital cochlear implant clinic. Patients: Results for 75 consecutive patients up to age 5 years who underwent implantation were included in the study. Intervention: Patients received a 22-electrode cochlear prosthesis and were seen by the clinic for regular tune-up and assessments. Home-and school-based habilitation was recommended by the clinic. Main Outcome Measures: Speech perception measures were classified on a five-point scale to allow for different evaluation procedures at different ages and developmental stages. Results: The incidence of motor and cognitive delays were fairly evenly spread across etiologic factors, except for cytomegalovirus, which had a much higher than average incidence. Children with motor and/or cognitive delays were significantly slower than other children in the development of speech perception skills after implantation. Etiologic factors did not have a statistically significant effect on speech perception outcome. Conclusions: It is likely that central pathologic states account for a substantial part of the variance among children using cochlear implants. Specific indicators of central pathologic states should be used to assess a child's prognosis in preference to less specific information based on etiologic factors alone.
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    Speech perception outcomes for older patients using the nucleus cochlear implant [Abstract]
    Tari, S. ; Weatherby, L. ; Winton, L. ; Hollow, R. ; Krauze, K. ; Winfield, E. ; Dowell, R. C. ; Clark, Graeme M. ( 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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    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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    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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    Hearing levels and speech perception prior to cochlear implantation - are they predictive of outcomes for adult implant users?
    Dowell, Richard C. ; Winton, Elizabeth ; Ling, Caroline ; Hollow, Rod ; COWAN, ROBERT ; Clark, Graeme M. ( 2000)
    As the speech perception results obtained for adults using multichannel cochlear implants have improved, people with a wider range of hearing losses are now considering implantation. In the mid-1980s, most adults undergoing cochlear implantation had little or no residual hearing. This made selection and counselling relatively straightforward as any level of hearing obtained through use of the cochlear implant could be considered as a benefit in such cases. Most patients evaluated for implantation today have some degree of useful residual hearing, and may be reliant on this hearing to varying degrees in their everyday life. In essence, they have something to lose if their postoperative performance is poor. In counselling these patients, it would be most helpful to have reliable predictors of postoperative performance. A number of factors such as duration of profound hearing loss, congenital profound hearing loss, and certain aetiologies (eg, head injury) have shown significant links with outcomes in previous studies.