Graeme Clark Collection
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ItemContributing factors to improved speech perception in children using the nucleus 22-channel cochlear prosthesis( 1997)It has been established that use of multiple-channel intracochlear implants can significantly improve speech perception for postlinguistically deafened adults. In the development of the Nucleus 22-channel cochlear implant, there have been significant developments in speech processing strategies, providing additional benefits to speech perception for users. This has recently culminated in the release of the Speak speech processing strategy, developed from research at the University of Melbourne. The Speak strategy employs 20 programmable bandpass filters which are scanned at an adaptive rate, with the largest outputs of these filters presented to up to ten stimulation channels along the electrode array. Comparative studies of the Speak processing strategy (in the Nucleus Spectra-22 speech processor), with the previously-used Multipeak (Multipeak) speech processing strategy (in the Minisystem-22 speech processor), with profoundly deaf adult cochlear implant users have shown that the Speak processing strategy provides a significant benefit to adult users both in quiet situations and particularly in the presence of background noise. Since the first implantation of the Nucleus device in a profoundly hearing-impaired child in Melbourne in 1985, there has been a rapid growth in the number of children using this device. Studies of cochlear implant benefits for children using the Nucleus 22-channel cochlear implant have also shown that children can obtain significant benefits to speech perception, speech production and language, including open-set understanding of words and sentences using the cochlear implant alone. In evaluating contributing factors to speech perception benefits available for children, four specific factors are important to investigate: (1) earlier implantation -resulting from earlier detection of deafness; (2) improved hardware and surgical techniques -allowing implantation in infants; (3) improved speech processing, and (4) improved habilitation techniques. Results reported previously have been recorded primarily for children using the Multipeak strategy implemented in the MSP speech processor. While it is important to evaluate the factors which might contribute to improvements in speech perception benefits, an important question is the effect of improved speech processing strategy, since this will determine what is perceived through the device. Given that adult patients changing to the Spectra speech processor had also shown improved perception in noisy situations, and the fact that children are in general in noisy environments in the classroom setting for a large proportion of their day, it was of obvious interest to evaluate the potential for benefit in poor signal-to-noise ratios from use of the Speak processing strategy and from specific training in the ability to perceive in background noise. The study was aimed at evaluating whether children who were experienced in use of the Multipeak speech processing strategy would be able to changeover to the new Speak processing strategy, which provides a subjectively different output. Secondly, the study aimed to evaluate the benefits which might accrue to children from use of controlled habilitation in background noise.
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ItemThe Melbourne Cochlear Implant Clinic program(Singular Publishing, 1997)The Melbourne Cochlear Implant Clinic program involves a multidisciplinary clinical team, collaborating with those engaged in more fundamental research, and with the biomedical company Cochlear Limited. This chapter reflects the contributions of many professionals to managing children with cochlear implants.
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ItemIntroduction(Singular Publishing, 1997)From the time single-channel cochlear implants were first implanted in children in the early 1980s in Los Angeles (Laxford et al 1987) closely followed in 1985 by the multiple-channel cochlear implant in Melbourne (Clark et al 1987a, 1987b) there has been a considerable expansion in the work to apply the multiple-channel cochlear implant to infants and young children.
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ItemEthical issues(Singular Publishing, 1997)The ethics of cochlear implantation in infants and children is an important issue which has received a lot of attention, in particular from the signing deaf community and their advocates. Many of the issues raised by the signing deaf community are in regard to human experimentation and are therefore ethical in nature. Others are concerned with whether it is natural to have a hearing loss, and this goes beyond the realm of ethics. This chapter examines cochlear implantation in children in light of generally accepted ethical principles.