Graeme Clark Collection

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    Speech cues for cochlear implantees: spectral discrimination
    Henry, Belinda, A. ; McKay, Colette M. ; McDermott, Hugh, J. ; Clark, Graeme M. (Monduzzi Editore, 1997)
    The relationship between the ability of cochlear implantees to perceive speech and their ability to discriminate between stimulation on adjacent electrodes was investigated. Speech perception ability was assessed with monosyllabic words in 8 users Nucleus cochlear prosthesis. The ability of these subjects to discriminate between stimulation on adjacent electrodes, in of random loudness differences between electrodes was determined. Results were averaged in the apical, mid and basal regions of the cochlea. Regression analysis showed that speech perception ability and electrode discrimination ability were correlated in the apical to mid region of the cochlea. but the two factors were not correlated in the basal region. Therefore, these results suggest that implantees require the ability to discriminate between stimulation on adjacent electrodes in the apical to mid region of the cochlea in order to achieve high speech perception scores.
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    A new algorithm for voicing detection and voice pitch estimation based on the neocognitron
    Moxham, James R. E. ; Jones, Peter A. ; McDermott, Hugh D. ; Clark, Graeme M. ( 1992)
    Over the last decade cochlear implants have been used increasingly to restore hearing to the profoundly deaf. One of the more widely used implants is the Nucleus multi-electrode implant, developed by the University of Melbourne and Cochlear Pty. Ltd. The speech processor used with this implant is the MSP, programmed with the multipeak strategy. This device incorporates circuits to estimate the fundamental frequency (FO) of speech signals, and to decide whether voicing is present. This paper describes a new FO estimator and voicing detection algorithm based on the neocognitron; a neural network modelled on the retina and early visual system. Performance was compared with that of three other FO estimation algorithms: linear predictive coding (LPC), cepstral analysis and the algorithm used in the Multipeak-MSP processor. For the speech samples tested, the neocognitron performed more reliably than the other three systems. On the basis of these results, this work may be able to provide benefits to existing and future cochlear implant users.