Graeme Clark Collection

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Author: Shepherd, Robert × End date: 1997 × Type: Conference Paper × Subject: cochlear implants ×

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    Peri-modiolar electrode arrays: a comparison of electrode position n the human temporal bone
    Shepherd, R. K. ; Treaba, C. G. ; Cohen, L. ; Pyman, B. ; Huigen, J. ; Xu, J. ; Clark, Graeme M. (Monduzzi Editore, 1997)
    This paper describes a radiologic evaluation of three types of peri-modiolar arrays, comparing their trajectory within the scala tympani with a standard Mini-22 electrode. All peri-modiolar arrays were found to lie closer to the modiolus for much of their insertion length compared with the standard array. While one design showed evidence for the potential of increased insertion trauma, two designs produced satisfactory results. Although further electrode development, temporal bone and histopathologic studies arE required, it would appear that the benefits of peri-modiolar electrode arrays will be realised clinically.
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    Electrical stimulation of the auditory nerve: stimulus induced reductions in neural excitability [Abstract]
    Shepherd, R. K. ; Clark, Graeme M. ( 1987)
    Electrical stimulation of the auditory nerve elicits highly synchronised neural activity (Javel et al., in press). As the stimulus current is increased the neural response becomes highly deterministic with every current pulse eliciting a spike even at stimulus rates of 600-800 pulses per second (pps). Our previous acute experimental studies have shown that high stimulus rates (> 200 pps) and high stimulus currents (> 1.0 mA) can result in temporary and sometimes permanent reductions in the excitability of the auditory nerve (Shepherd and Clark, 1986). The present study was designed to examine the mechanisms underlying these stimulus induced reductions in excitability. These results will have implications for the maximum safe and effective stimulus rates that can be employed in cochlear implants.