Graeme Clark Collection
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ItemImplantation of the new nucleus C1-3 receiver stimulator and electrode array [Abstract]( 1997)There is an important need to fix the cochlear implant electrode array at a site close to the cochlea, so that the electrode will not slide out, or be subject to differential movement with growth changes. Fixation sites have been in the region of the posterior root of the zygoma and the floor of the antrum. Fixation has been by Dacron mesh ties platinum wire ties, or clips inserted with-special instruments. Biological cements have previously been tried but found to be toxic. The most ideal site is in the region of the cochleostomy.
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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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ItemThe development of auditory comprehension in children after receiving a cochlear multiple-channel implant( 1992)Since late 1989, half the cochlear implant patients at the Royal Victorian Eye and Ear Hospital have been young children. There is a gradual improvement of auditory comprehension in most cases using the criteria of environmental sound detection, as well as, prosody, high frequency phoneme and word discrimination. The rate of improvement and final result depend on the duration of deafness, presence of residual hearing, and quality of auditory-oral habilitation. Younger children usually progress more quickly than older children. Some adolescents who use Total Communication and who have no residual hearing, achieve assistance with lipreading. Children with Usher's Syndrome should be actively encouraged to participate in auditory-oral habilitation should they become totally deaf or blind.
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ItemCochlear implant skin flap design: the vascular pattern of the postauricular region( 1993)Cochlear implantation proved to be a safe surgical procedure. Complications are rare, but the most significant of them are skin flap related problems, occasionally resulting in removal of the device. To evaluate the vascular pattern of the scalp and its implications for cochlear implant skin flap design we performed a dye injection study on cadavers. Our results on ten specimens indicate, that the blood supply for the skin in the postauricular region is provided inferiorly by indirect musculocutaneous perforators, posteriorly by the occipital artery, superiorly by the superficial temporal artery and anteriorly by the network around the base of the auricle and by cutaneous branches of the postauricular artery. A flap for cochlear implantation raised in this region cannot be based on one single axial source artery and has to rely on a variable number of different arterial contributors, resulting in a combination of random, axial and/or musculocutaneous flap. Inferiorly-based flaps as the inverted U shaped or the extended enaural (Hannover) are considered to be superior to the C-shaped anteriorly-based flap.