Graeme Clark Collection

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    Speech perception in implanted children: effects of speech processing strategy and residual hearing
    Meskin, T. ; Rance, G. ; Cody, K. ; Sarant, J. ; Larratt, M. ; Latus, K. ; Hollow, R. ; Rehn, C. ; Dowell, R.C. ; Pyman, B. ; Gibson, W.P.R. ; Clark, Graeme M. ; Cowan, Robert S. C. ; Barker, E. J. ; Pegg, P. ; Dettman, S. ; Rennie, M. ; Galvin, K. (Mendoza Editor, 1997)
    The ability of implanted children to adapt to different speech processing strategies has been demonstrated for the Nucleus implant system. Children previously experienced with the Multipeak speech processing strategy. were able to gain significant improvements in consonant, word and sentence perception using the Speak speech processing strategy. suggesting some degree of neural plasticity in neural-auditory coding. Of 192 implanted children with different degrees of preoperative residual hearing, 65% were found to obtain significant scores on open-set speech materials using electrical stimulation alone. Those children with more residual hearing had a greater probability of achieving open-set understanding and at a minimum level, perceived high frequency consonant information which would not have been available through conventional hearing aids.
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    Habilitation issues in the management of children using the cochlear multiple-channel cochlear prosthesis
    Galvin Karyn L. ; Dawson Pam W. ; Hollow Rod. ; Dowell Richard C. ; Pyman B. ; Clark Graeme, M. ; Cowan, Robert S. C. ; Barker, Elizabeth J. ; Dettman, Shani J. ; Blamey, Peter J. ; RANCE, GARY ; Zarant, Julia Z. ( 1993)
    Since 1985, a significant proportion of patients seen In the Melbourne cochlear Implant clinic have been children. The children represent a diverse population, with both congenital and acquired hearing-impairment, a wide-range or hearing levels pre-Implant, and an age range from 2 years to 18 years. The habilitation programme developed for the overall group must be flexible enough to be tailored to the Individual needs of each child, and to adapt to the changing needs or children as they progress. Long-term data shows that children are continuing to show Improvements after 5-7 years of device use, particularly In their perception of open-set words and sentences. Habilitation programs must therefore be geared to the long-term needs of children and their families. Both speech perception and speech production need to be addressed In the specific content of the habilitation program for any Individual child. In addition, for young children, the benefits or Improved speech perception should have an Impact on development of speech and language, and the focus of the programme for this age child will reflect this difference In emphasis. Specific materials and approaches will vary for very young children, school-age and teenage children. In addition, educational selling will have a bearing on the Integration of listening and device use Into the classroom environment.
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    Surgery for multielectrode cochlear implants
    Lehnhardt, E. ; Laszig, R. ; Webb, H. ; Franz, B. ; Pyman, B. ; Clark, Graeme M. ( 1987)
    For the surgery of the NUCLEUS Cochlear Implant (CI) in general anaesthesia we use a skin cut beginning at the bottom of the entrance to the outer ear canal, following the posterior circumference to a point nearly 12 o'clock. From here the incision runs superiorly to the tragus until two or three centimetres above the pinna base and in a wide smooth circle in direction to the occiput. The wide circle is necessary to get a distance of about 2 cm away from the package and also to guarantee the blood supply by the occipital artery and by the postauricular artery as well.
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    Histopathology following electrode insertion and chronic electrical stimulation
    Shepherd, R. K. ; Clark, Graeme M. ; Pyman, B. C. ; Webb, R. L. ; Murray, M. T. ; Houghton, M. E. (Raven Press, 1985)
    We have examined a number of safety issues associated with cochlear implants. This work has been primarily designed to evaluate the histopathological effects of intracochlear electrode implantation and chronic electrical stimulation. The results of these studies may be summarized as follows: 1) The insertion of the banded free-fit scala tympani array into human cadaver temporal bones produces minimal damage, occurring primarily to a localized region of the spiral ligament. This damage would not result in significant neural degeneration and thus, would not compromise the efficacy of the multiple channel device; 2) chronic intracochlear electrical stimulation for continuous periods of 500 to 2000 hours, using charge balanced biphasic current pulses developing charge densities of 18-32 }?C/cm2. geom./phase, does not adversely affect the spiral ganglion cell population; 3) labyrinthine infection severely reduces the viable spiral ganglion cell population; 4) the formation of new bone present in approximately half of the animals we have implanted --is not associated with electrical stimulation per se; 5) scanning electron microscope studies of electrodes subjected to long periods of intracochlear electrical stimulation reveals minimal platinum dissolution when compared with unstimulated control electrodes, and electrodes that have been stimulated for similar periods in inorganic saline.