Graeme Clark Collection

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    Cognitive processing in children using cochlear implants: the relationship between visual memory, attention, and executive functions and developing language skills
    Surowiecki, Vanessa N. ; SARANT, JULIA ; MARUFF, PAUL ; Blamey, Peter J. ; Busby, Peter A. ; Clark, Graeme M. ( 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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    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 effect of language knowledge on speech perception: what are we really assessing?
    Sarant, Julia Z. ; Blamey, Peter J. ; Cowan, Robert S. ; Clark, Graeme M. ( 1997)
    Objective: The authors examined whether open-set speech perception scores are limited by knowledge of vocabulary and syntax and further considered whether remediation of vocabulary and syntax will increase open-set speech perception scores. Study Design: This was a repeated-measures study design in the setting of a primary (elementary) school for the hearing impaired. Patients: The study population was composed of three hearing-impaired children using Nucleus 22-channel cochlear implant. Intervention: Intervention used was language remediation sessions. Main Outcome Measures: The main outcome measures were assessment of auditory-alone speech perception benefit using open-set words and sentences and assessment of syntactic knowledge using the Test of Syntactic Ability. Outcome measures were applied before and after remediation. Results: Child 1 and child 2 showed a significant postremediation improvement in their overall scores on the Test of Syntactic Ability and in their ability to perceive words learned during remediation. Child I and child 2 also showed a significant improvement in their scores on a modified Bamford-Kowal-Bench open-set sentence test, which specifically targeted grammatical constructs trained in remediation sessions. Conclusions: Remediation of language knowledge deficits significantly improved open-set speech perception for two children, suggesting a need to include language remediation in cochlear implant habilitation programs.
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    Speech perception results for children with implants with different levels of preoperative residual hearing
    Cowan, Robert S. C. ; DelDot, J. ; Barker, J. Z. ; Barker, Elizabeth J. ; Sarant, Julia Z. ; Pegg, P. ; Dettman, S. ; Galvin, K. L. ; Rance, G. ; Hollow, R. ; Dowell, R. C. ; Pyman, B. ; Gibson, W. P. R. ; Clark, Graeme, M. ( 1997)
    Objective: Many reports have established that hearing-impaired children using the Nucleus 22 channel cochlear implant may show both significant benefits to lipreading and significant scores on open-set words and sentences using electrical stimulation only. These findings have raised questions about whether severely or severely-to-profoundly deaf children should be candidates for cochlear implants. To study this question, postoperative results for implanted children with different levels of preoperative residual hearing were evaluated in terms of speech perception benefits. Study Design/Setting: A retrospective study of the first 117 children, sequentially, to undergo implantation in the Melbourne and Sydney Cochlear Implant Clinics was undertaken. All children had been assessed by and received their implants in a tertiary referral centre. Main Outcome Measures: To assess aided residual hearing, the children were grouped into four categories of hearing on the basis of their aided residual hearing thresholds measured preoperatively. To assess benefits, the scores of children on standard speech perception tests were reviewed. As different tests were used for children with different ages and language skills, children were grouped into categories according to the level of postoperative speech perception benefit. Results: The results showed that children in the higher categories of aided preoperative residual hearing showed significant scores on open-set word and sentence perception tests using the implant alone. For children in lower categories of aided residual hearing, results were variable within the groups. More than 90% of children with implants with aided residual hearing thresholds in the speech range above I kHz achieved open-set understanding of words and sentences. Conclusion: While the results of this preliminary study confirm previous findings of differential outcomes for children with different levels of preoperative residual hearing, they suggest that children with severe to profound hearing impairments should be considered for cochlear implantation.
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    Within-subject comparison of speech perception benefits for congenitally deaf adolescents with an electrotactile speech processor and a cochlear implant
    SARANT, JULIA ; COWAN, ROBERT ; BLAMEY, PETER ; GALVIN, KARYN ; Clark, Graeme M. ( 1996)
    This study assessed speech perception benefits for three congenitally deaf adolescents who used an electrotactile speech processor (Tickle Talker™) and subsequently went on to use a Nucleus Minisystem 22 cochlear implant. Both devices provided significant and comparable benefits for all children in the device plus lipreading condition. All children benefited from the additional information provided by either the Tickle Talker™ or the cochlear implant, and were able to perceive speech information with these devices that was not available through either aided residual hearing or lipreading. None of the three children were able to understand open-set words or sentences using either hearing aids alone or Tickle Talker™ alone, without the aid of lipreading. Two of the children showed significant open-set speech perception benefits while using their cochlear implant alone.
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    Issues in the development of multichannel tactile devices for hearing-impaired children and adults
    Cowan, Robert S. C. ; Galvin, Karyn L. ; Sarant, Julia Z. ; Blamey, Peter J. ; Clark, Graeme M. ( 1995)
    Levitt, Pickett and Houde (1980), in their landmark monograph, noted that the history of tactile aid development has been characterized by periodic bursts of enthusiasm and research, often culminating in identification of new avenues to be explored for improving tactile perception of speech. While several research groups have maintained long-term interest in tactile research (Boothroyd, 1985; Oller, Payne, & Gavin, 1980; Saunders, 1985), there was a marked increase in reports of new multichannel tactile devices during the 1980s (reviewed in McGarr, 1989). This upsurge may have been spurred in part by the rapid increase world-wide in the number of hearing-impaired children and adults using cochlear implants as everyday communication devices, and the perceived need for a non-surgical approach to assisting hearing-impaired children. Despite this increase in tactile research, no tactile device has yet achieved widespread commercial use by the hearing-impaired community. It is, therefore, of interest to question why cochlear implants have been more widely accepted than tactile devices.
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    Articulation accuracy of children using an electrotactile speech processor
    Galvin, Karyn L. ; Cowan, Robert S. C. ; Sarant, Julia Z. ; Tobey, Emily A. ; Blamey, Peter J. ; Clark, Graeme M. ( 1995)
    Objective: Use of wearable tactile speech perception devices is suggested to help overcome the difficulties in speech production resulting from severe and profound hearing impairment in children. This suggestion is based on the assumption that subjects can use tactile input in isolation, or in combination with information from residual aided hearing, to monitor and modify their speech. The present study evaluated the benefits to articulation provided through use of a multichannel electrotactile device (“Tickle Talker™”). Design: Six profoundly hearing-impaired children were videotaped speaking with the Tickle Talker on and with the Tickle Talker off during conversations with their audiologist. Five of the subjects also wore their binaural hearing aids during all recorded conversations. The number of vowels, consonants, and overall phonemes correctly articulated by each child in the two conditions were compared. Results: One subject improved articulation of initial consonants and initial phonemes; one subject improved articulation of total vowels, total consonants, initial consonants, total phonemes, and initial phonemes; and a third subject improved articulation of total vowels and medial phonemes. Conclusions: Use of on-line tactile feedback from the Tickle Talker may benefit the articulation accuracy of some children, and the device may therefore be suitable to use with children who have not responded to more traditional speech training techniques.
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    The progress of children using the multichannel cochlear implant in Melbourne
    Cowan, R. S. C. ; Dowell, R. C. ; Hollow, R. ; Dettman, S. J. ; Rance, G. ; Barker, E. J. ; Sarant, J. Z. ; Galvin, K. L. ; Webb, R. C. ; Pyman, B. C. ; Cousins, V. C. ; Clark, Graeme M. ( 1995)
    Multi-channel cochlear implantation in children began in Australia in 1985 and there are now close to 4000 profoundly deaf children and adolescents using the Australian implant system around the world. The aim of the implant procedure is to provide adequate hearing for speech and language development through auditory input. This contrasts with the situation for adults with acquired deafness where the cochlear implant aims to restore hearing for someone with well-developed auditory processing and language skills. As with adults, results vary over a wide range for children using the Multi-channel implant. Many factors have been suggested that may contribute to differences in speech perception for implanted children. In an attempt to better understand these factors, the speech perception results for children implanted in Melbourne were reviewed and subjected to statistical analysis. This has indicated that the amount of experience with the implant and the length of sensory deprivation are strongly correlated with perceptual results. This means that younger children are likely to perform better with an implant and that a number of years of experience are required for children to reach their full potential. The results have also indicated that educational placement and management play a crucial role in children reaching their potential. Overall, 60% of the children and adolescents in the study have reached a level of open-set speech understanding using the cochlear implant without lipreading.
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    Within-subject comparison of speech perception benefits with a multiple-channel cochlear implant and tactile device
    Sarant, J. Z. ; Cowan, R. S. C. ; Blamey, P. J. ; Galvin, K. L. ; Clark, Graeme M. ( 1995)
    In order to adequately advise prospective cochlear implant patients and their families, a clinician must have a good knowledge of the potential for particular individuals to benefit from cochlear implants and other alternatives.
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    Speech self-monitoring by children using an electrotactile speech processor
    Galvin, K. L. ; Cowan, R. S. C. ; Sarant, J. Z. ; Tobey, E. A. ; Blamey, P. J. ; Clark, Graeme M. ( 1995)
    For the profoundly and severely-to-profoundly hearing impaired child, lipreading and hearing aids are not always sufficient to develop adequate speech perception and production skills. Tactile devices have been investigated as a source of supplementary speech information, with most research focusing on speech perception benefits. However, speech production difficulties are also a major issue for these children, and research into tactile devices should include investigation of the option to use them as speech production aids. This paper will present the results from an initial examination of the suitability of one tactile device for speech production monitoring.