Graeme Clark Collection

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Author: Dowell, Richard × Start date: 2000 × Type: Conference Item × Subject: otolaryngology × Subject: speech perception ×

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    Factors affecting speech perception outcomes for older children using multichannel cochlear implants
    Dowell, Richard C. ; Dettman, Shani J. ; Hill, Katie ; Winton, Elizabeth ; Hollow, Rod ; Clark, Graeme M. ( 2002)
    Experience with cochlear implantation in early-deafened teenagers or young adults has been somewhat disappointing, however, in recent years a proportion of older children have demonstrated excellent speech perception performance. There appears to be a wide gap between the good and poor performers within this group. It is important to investigate the possible factors influencing performance so that adolescents and their families are able to make informed decisions regarding cochlear implant surgery. This study considered a number of factors in a group of 25 children implanted in Melbourne between the ages of 8 and 18 years. Each subject completed open set speech perception testing using BKB sentences before and after implantation and pre-operative language testing using the Peabody Picture Vocabulary Test. Data were collected regarding the type of hearing loss, age at implant, age at hearing aid fitting, audiometric details, and the pre-and postoperative communication mode. Multivariate analysis suggested that three factors have a significant predictive value for post-implant speech perception: pre-operative open-set sentence score, duration of profound hearing loss and equivalent language age. These three factors accounted for 66% of the variance in this group. The results of this study suggest that children who have useful pre-implant speech perception, and higher age-equivalent scores on language measures, would be expected to do well with a cochlear implant. A shorter duration of profound hearing loss is also advantageous. Mean speech perception scores for the older group were not significantly different from younger children.
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    Initial speech perception results with the new multipeak speech processor for the 22-electrode cochlear prosthesis [Abstract]
    Webb, Robert L. ; Dowell, Richard C. ; Seligman, Peter M. ; Whitford, Lesley A. ; Clark, Graeme M. ( [1990])
    A new speech processor has been developed for the 22-electrode cochlear prosthesis by Cochlear Pty Ltd working in conjunction with the Department of Otolaryngology at the University of Melbourne. The new device, known as the MSP, combines smaller, more efficient hardware with a new speech coding scheme in an attempt to provide better speech perception in everyday environments for implant users. The MSP operates with the current implant device so there is no need for existing implantees to have revision surgery to make use of the new development. The multipeak speech coding scheme, which has been implemented in the MSP, provides information from three high frequency spectral bands, in addition to the parameters of voice pitch, amplitude and first and second formants which have been provided in the existing FOFIF2 coding scheme for the last four years. Initial speech perception results with research subjects have shown significant improvements in performance for the MSP over the older system (WSP III). The most encouraging result is that open-set speech perception in the presence of competing noise has improved substantially. For example, mean scores for BKB sentences in a 10 dB signal-to-noise ratio were 64% for the MSP and 31% for the WSP III. Further investigations have shown that both the hardware improvements and the new multipeak speech coding scheme have contributed significantly to the overall improvement in performance. Studies are continuing to analyse further the potential of the new system.