Graeme Clark Collection
Permanent URI for this collection
Search Results
1 - 10 of 18
-
ItemFactors affecting speech perception outcomes for older children using multichannel cochlear implants( 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.
-
ItemPost-implant habilitation for children using cochlear implants: effects on long-term outcome( 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.
-
ItemWhat factors contribute to successful outcomes for children using cochlear implants( 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.
-
ItemLatest results for adults & children using cochlear implants & future implications( 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.
-
ItemHearing levels and speech perception prior to cochlear implantation - are they predictive of outcomes for adult implant users?( 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.
-
ItemPerformance benefits and costs for children using cochlear implants and hearing aids [Abstract]( 1998)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 which has clearly established the benefits available (U.S. National Institutes of Health Consensus Statement 1995). Benefit has traditionally been considered as the direct impact of the cochlear implant procedure on speech perception, or in the case of children, on the use of that auditory information to develop understandable speech and to acquire a knowledge of language. As a consequence of continuing research to improve hardware and speech processing strategies, mean scores on open-set tests of monosyllables or sentence materials for implanted adults using the cochlear implant alone without lipreading have continued to show an upwards trend. In response to the increased mean scores in quiet, perception tests in background noise are now being used as a more accurate direct measure of the potential benefits of cochlear implants to severely-to-profoundly hearing-impaired candidates. Consideration should also be given to indirect benefits, such as reduction in the stress of listening and lipreading, improved performance at work, enhanced opportunity to maintain speech, or in children to develop speech which is understandable to the general community, and the social effects of reducing the isolating effects of profound deafness. Measurement of indirect benefit can be combined with an analysis of the costs of the procedure, enabling evaluation of the implant procedure from a cost-utility standpoint, and a comparison of outcomes using other technologies such as hearing aids. This study will present data on direct and indirect benefits for hearing-impaired children using Nucleus cochlear implant systems, and compare this data with benefits shown for similarly hearing impaired children using hearing aids. The significance of these results to cost-effective delivery of services will be discussed.
-
ItemEvaluation of direct and indirect benefits in the selection of cochlear implant candidates [Abstract]( 1998)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 which clearly established the benefits available (U.S. National Institutes of Health Consensus Statement 1995). Benefit has traditionally been considered as the impact of the cochlear implant procedure on hearing, and in the case of children, on the use of that hearing to develop speech and language. However, as a result of continuing research, improvements have been realised both in hardware and speech processing. As a direct consequence of these improvements, the mean open-set implant-alone speech perception scores for implanted adults have continued to increase. In response to the increased mean scores shown by adult cochlear implant users in quiet, perception tests in background noise are now being used as a direct measure of the potential benefits of cochlear implants available to severely-to-profoundly hearing-impaired candidates. In addition, consideration in candidature should also be given to indirect benefits, such as reduction in the stress. of listening and lipreading, improved performance at work, enhanced opportunity to maintain or in children to develop speech which is understandable to the general community, and the social effects of reducing the isolating effects of profound deafness. Measurement of indirect benefit can be combined with a costing study, enabling evaluation of the implant procedure from a cost-utility standpoint, and comparison of outcomes using other technologies such as hearing aids. The use of new approaches to candidature, including new measures of direct and indirect benefit is reported using data from the Melbourne cochlear implant program.
-
ItemCurrent speech perception benefits for adults using the speak strategy with the nucleus 22-channel cochlear implant( 1997)Present day recipients of the Nucleus 22-channel cochlear implant make use of the SPEAK speech processing strategy in the Spectra 22 speech processor. Introduced in 1994, the SPEAK strategy is based upon research conducted at the University of Melbourne and the Bionic Ear Institute. This paper compares the pre-and post-operative speech perception abilities of adults who have used the SPEAK speech processing strategy since the 'start-up' of their cochlear implant system. Data was analysed from open-set sentence and word tests administered pre-operatively and at regular intervals postoperatively. Patients showed significant improvement in their ability to recognise speech, when listening with the cochlear implant without lipreading, within the first two weeks. Mean scores for open-set sentences were 15% preoperatively and 64% two weeks after initial programming.
-
ItemSpeech perception in implanted children: effects of preoperative residual hearing and speech processing strategy [Abstract]( 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.
-
ItemResults of multichannel cochlear implantation in very young children [Abstract]( 1995)Most researchers and clinicians working in the cochlear implant field have assumed that profoundly deaf children will have a better prognosis in terms of speech perception, speech production and language development, implanted at as young an age as possible. However, it has been difficult to gather direct evidence for this hypothesis due to the problems in assessing children under the age of five years with formal tests.