Graeme Clark Collection
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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.
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ItemThe use of click-ABR and steady state evoked potentials for hearing assessment in young cochlear implant candidates [Abstract]( 1997)The accurate assessment of hearing thresholds in prospective cochlear implant candidates is essential. As the minimum age of implantation has reduced, audiologists have been faced with the complicated task of obtaining precise audiometric information in children whose immaturity may severely restrict the assessment process. Clearly for these young candidates, there is a place for a reliable, objective measure of residual hearing in the pre-operative test battery. This paper examines the degree of accuracy with which the click-ABR and the steady-state evoked potential (SSEP) techniques can provide estimates of hearing level in subjects with several profound hearing loss.
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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.
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ItemSpeech perception of hearing aid users versus cochlear implantees [Abstract]( 1997)Recent improvements in speech recognition for profoundly deaf, cochlear implant patients have suggested that some people with a severe hearing impairment would be more successful with a cochlear implant than a hearing aid. Unfortunately, no studies have investigated the speech perception of the severely hearing impaired in order compare their speech perception abilities with those of cochlear implant users. To investigate this area further, a detailed investigation of the hearing aid performance of people with a severe hearing loss is being conducted in the Department of Otolaryngology at The University of Melbourne. The range of hearing losses for this study was defined as a pure tone average of greater than 6OdBHL, but no worse than 100dBSPL in the better ear. At present thirty-five (n=35) participants have been involved in this study. Each participant took part in a series of speech perception tests which included 24 consonant recognition, 11 vowel recognition, CNC words, CUNY sentences, and the connected speech test.
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ItemSpeech perception benefits for implanted children with preoperative residual hearing [Abstract]( 1995)Since the implantation of the first children with the Nucleus 22-channel cochlear prosthesis in Melbourne in 1985, there has been rapid expansion in the number of implanted children world-wide. Improved surgical technique and experience in paediatric assessment and management have contributed to a trend to implant very young children. At the same time there has also been continuing development of improved speech processing strategies resulting in greater speech perception benefits. In the Melbourne program, over 60% of children obtain significant scores on open-set word and sentence tests using their cochlear implant alone without the aid of lipreading. As parents and professionals have become aware of these improved benefits to speech perception benefits in profoundly deaf children, there have been requests to consider implanting severely-to-profoundly deaf children. In these children with higher levels of residual hearing, only those children with poorer-than-expected performance on speech perception tests using hearing aids have been considered for surgery. A number of such cases have now been implanted in the Melbourne program. The speech perception benefits for this group are reported and are being compared with benefits for the profoundly deaf group of children.
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ItemSpeech perception benefits for children using the Speak speech processing strategy in quiet and noise [Abstract]( 1995)The Speak speech processing strategy, based on the Spectral Maxima Speech Processor (SMSP) developed at the University of Melbourne, has now been implemented in the Spectra 22 speech processor developed by Cochlear Pty Limited, and clinical trials of both patients changing from the previous Multipeak strategy to Speak and patients starting up with. Speak have been conducted. Results in adult patients changing to Speak have shown significant improvements in speech perception in quiet and particularly in background noise as compared with Multipeak. Preliminary studies with children changing from Multipeak to Speak strategy, measured over a 10 month period, have also shown significant benefits from use of the Speak scheme in both quiet and noisy test situations. Results of follow up studies of these children after more than one year experience with the Speak processing strategy are presented. Statistical analysis of performance over time suggests that an increase in benefit is observed in children after additional experience with the Speak processing strategy. In addition, results for children who have used only the Speak processing strategy from the time of implantation are also presented. The results confirm that the Speak processing strategy provides significant benefits in quiet, and particularly in the presence of background noise for both groups of patients.
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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. if 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. Recent results with older children have supported the view that early implantation may provide the optimal outcome in most cases. The implantation of very young children raises two areas of concern that do not apply in adults and older children: accurate assessment of degree of hearing loss and auditory potential; and postoperative assessment of outcomes. This paper will describe research results from the University of Melbourne which address these issues and present results for children implanted as young as eighteen months of age.
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ItemSpeech perception benefits for children using the 22-channel Melbourne/cochlear hearing prosthesis [Abstract]( 1993)In 1985; the first child was implanted with the Cochlear 22-channel cochlear prosthesis at the University of Melbourne Royal Victorian Eye & Ear Hospital Cochlear Implant Clinic. There are now 42 children who have received the device in Melbourne. Analysis of patient details for these children show a very heterogeneous group, with a wide range in age, hearing thresholds, duration of deafness and aetiology. The major aetiologies found were either a congenital profound deafness.; or a hearing loss due to meningitis. In all but 3 cases, the children are using 15 or more electrodes in the array. Speech perception benefits have been analyzed according to a six-level hierarchical classification scheme. All of-the children achieved a minimum benefit of discrimination of suprasegmental information (Category 2), and 59% of the children achieved open-set understanding of unfamiliar speech material without the aid of lip-reading (Categories 5 & 6). Detailed analysis suggests that the majority of children achieving open-set speech perception benefits had more than one year of experience with their implant. and less than seven years of profound deafness prior to implantation.
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ItemFactors associated with open-set speech perception in children using the Cochlear multiple-channel prosthesis [Abstract]( 1993)Since 1985, nearly 100 children have received the 22-channel cochlear prosthesis from the Melbourne and Sydney cochlear implant clinics. These two clinics account for the bulk of casesin Australia, and have similar management philosophies and selection criteria. The patient population represents a variety of etiologies, and ranges in age from 2 - 18 years of age. Bothcongenital and postlinguistic hearing losses are included. In order to assess benefit to speech perception in such a diverse group, the children's results have been tabulated according to a six level hierarchical scale of speech perception achievement. The scale ranges from category I,detection of sound only, to category 6, which includes significant perception scores for open-setwords and sentences. Analysis of the results shows that the majority of the children are achieving open-set speech perception benefits, and that results continue to improve with additional experience with their devices. There are a number of contributing factors to these open-set speech� perception results which have impact both on selection issues and on habilitation with different age ranges �of patients.
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ItemFuture directions in the clinical application of multichannel cochlear prostheses [Abstract]( 1992)Three main areas of work at the University of Melbourne relating to the clinical application of multichannel cochlear prostheses will be discussed. Speech perception results for 40 children and adolescents implanted with the Nucleus multichannel device will be presented with an analysis of potentially predictive clinical factors. Overall results have shown that 60% of the children have developed useful open-set speech recognition ability without visual cues. Due to the improved speech perception for postlinguistically deafened adult cochlear implant patients, the multichannel implant has become a viable alternative for patients with some useful residual hearing. A "bimodal" speech processor which provides acoustic output for the residual hearing ear and electrical output for the cochlear implant will also be discussed. This device provides a flexible, programmable acoustic processor which can make use of feature coding aspects of the implant processing. The "bimodal" device has also addressed problems of incompatibility of the implant signal with the acoustic signal from conventional hearing aids. Results for the new "Spectral Maxima Speech Processor" (SMSP) will also be presented. The SMSP has shown improved speech perception performance in quiet and in noise when compared with the MSP (MULTIPEAK) system, currently in use with the Nucleus device. Results for four subjects with the SMSP showed mean scores of 57.4% for open-set monosyllabic words in quiet, and 78.7% for open-set sentences in a 10 dB signal-to-noise ratio