Graeme Clark Collection
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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.
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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, 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.
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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.
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ItemSpeech perception results for children changing from multipeak to SPEAK speech processing strategy [Abstract]( 1996)In mid-1994, a new speech processing strategy termed SPEAK was introduced for the Nucleus Spectra-22 cochlear prostheses. To compare benefits in implanted children changing to the SPEAK strategy, speech perception in a group of twelve children from Melbourne and Sydney was evaluated. The children were assessed in quiet and in background noise.
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ItemEffects of habilitation in background noise on speech perception in implanted children [Abstract]( 1996)Evaluation of a group of children using the Nucleus multichannel cochlear implant, evaluated over a two year period, showed that improvements to speech perception scores in poor signal-to-noise conditions could be achieved through use of the Speak speech processing strategy. The increases were noted particularly in perception of consonant place features in poor signal-to-noise conditions. However, overall scores were still lower than for hearing in quiet.
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ItemFactors affecting speech perception in children cochlear 22-channel cochlear prosthesis [Abstract]( 1996)Since the implantation of the first children with the Nucleus 22-channel cochlear prosthesis in Melbourne in 1985, there have been rapid expansion world-wide in the number of children using this implant system. Longer-term experience with implanted children has led to improvements in paediatric assessment and management. Speech processing strategies have also been improved, resulting in a series of increases in speech perception benefits.
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ItemSpeech perception results for implanted children with different levels of preoperative residual hearing [Abstract]( 1996)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 suggestions that severely or severely-to-profoundly deaf children might benefit more from a cochlear implant than conventional amplification.
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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.
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ItemComparative performance of children using the cochlear 22-channel implant and 8-channel 'Tickle Talker'( 1992)Direct comparison of "Tickle Talker" and Cochlear Implant users is problematic, due to difficulties in matching groups of children for hearing loss, age, duration of deafness, speech perception and language skills, and educational placement. However, two studies were undertaken to compare and contrast potential benefits available from these two devices. In the first study, a number of children from one educational setting were evaluated over a six month period. Half of the children used the multiple channel cochlear implant, while the other half used the multiple channel "Tickle Talker". The number of training sessions, clinicians involved, type of training provided, and overall management philosophy were identical for both devices. Comparison of progress of these two groups of children demonstrates that both devices are effective in improving' communication. However, differences were found with the tactile device being more limited in information provided and speech perception benefits. In the second study, two children who have used both devices were evaluated. These two children initially used the ''Tickle Talker" for periods up to two years, and subsequently had a multiple-channel cochlear implant. Similar habilitation was provided to these children with both devices, and measures of speech perception were taken at similar time periods. Results for one of the children, a prelinguistically deafened adolescent, already show similar benefits in terms of supplementation of lipreading for both devices. However, this patient has also shown some open-set word and sentence perception using the implant-alone. To date, this level of performance has not been achieved with the ''Tickle Talker". The results of these studies suggest a role for a multiple channel tactile device in a cochlear implant clinic as a training device for evaluating the ability of adults or children to integrate speech information presented through different sensory modalities. This could facilitate pre-implant evaluation of the potential for children to benefit from added speech information, which is often difficult to evaluate in congenitally deaf children.
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ItemDevelopment of an advanced electrotactile speech processor [Abstract]( 1992)Initial studies with a multiple channel electrotactile speech processor ('Tickle Talker') showed that profoundly hearing-impaired adults and children could achieve significant improvements on speech perception tests through use of tactual-encoded estimates of fundamental frequency, second formant frequency and amplitude envelope. Results showed that the device provided tactual cues which could be used to discriminate speech features such as vowel length and place, and consonant manner and voicing. However, discrimination of initial consonant voicing was not as consistent as for other features. Accurate discrimination of consonant voicing and manner (particularly high frequency information) is critical, since this Information is generally inaudible through hearing aids, and difficult to lipread.