Graeme Clark Collection

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Author: McDermott, Hugh × End date: 1999 × Type: Journal Item × Subject: cochlear implant × Subject: otology ×

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    Place pitch perception with multiple electrode cochlear implants: the use of concurrent activation of nearby electrodes to produce additional ptich percepts [Abstract]
    McDermott, Hugh J. ; McKay, Colette M. ( 1992)
    In multiple electrode cochlear implants, each electrode produces a pitch percept which is usually related monotonically to its distance from the round window. The number of these pitch percepts is limited by the number of usable electrodes and their discriminability, varying up to a maximum of 22 for the mini-system 22 implant but sometimes significantly less. A study on two implanted subjects in which the pitch of pulse trains on two concurrently activated nearby electrodes was compared with the pitch produced when each of the electrodes was activated on its own, showed that the pitch of the concurrently activated electrodes was different from each component electrode and was placed in an intermediate position. Furthermore the pitch of the concurrent stimulation could be altered by adjusting the relative current levels on the two component electrodes. This may partly explain the improvements, particularly in vowel discrimination, obtained with the SMSP strategy described in the accompanying paper.
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    Current advances in speech processing for the mini-system 22 implant [Abstract]
    McKay, Colette M. ; McDermott, H. J. ( 1992)
    The Spectral Maxima Sound Processor (SMSP) has been developed at the University of Melbourne for use with the mini-system 22 cochlear implant manufactured by Cochlear Pty Ltd. Studies with adult subjects have shown that perception of vowels, consonants, words. and sentences in quiet and in background noise is enhanced with the SMSP when compared with the MSP(MULJIPEAK) currently supplied for use with this implant. Studies comparing the ability of subjects to identify speakers and to identify intonation patterns have shown no reduction due to the SMSP's use of a constant rate of electrical stimulation. Qualitative remarks of subjects are consistent with improved perception in background noise and of degraded speech such as with TV and telephone use. They also report that environmental noises and music sound more natural. Further development of the SMSP strategy and formulation of new strategies are being facilitated by a new programmable processor utilising digital signal processing.