Graeme Clark Collection

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End date: 1997 × Start date: 1992 × Type: Conference Item × Subject: electrical stimulation × Subject: otolaryngology × Subject: otology ×

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    A stimulation of spatio-temporal firing across auditory nerve fibres
    Carter, T. D. ; Irlicht, L. S. ; Au, D. ; Clark, Graeme M. ( 1997)
    Present cochlear implant speech processing strategies give recipients a perception of sound inferior to that of the normal hearing population. Since it is beyond current technology to achieve an electrically evoked auditory-nerve output identical to that of normal hearing, stimulation strategies are limited to approximating certain features of the neural firing patterns. The importance of the spatio-temporal firing patterns of an ensemble of auditory nerve fibres to speech perception has been stated in previous studies (1,2). This paper utilises a composite model of the cochlea and hair-cell/auditory nerve transduction using artificial and speech signals as input to produce a spatio-temporal excitation pattern which represents the fluctuating firing probability of the auditory neurons. A model of electrical stimulation of the auditory nerve is then used to show how stimulation strategies currently used produce neural firing patterns qualitatively different to those produced by normal hearing. Our investigations indicate that it is possible to generate electrical stimulation parameters that cause the spatio-temporal responses of the neural population to better approximate normal hearing. These responses enable us to identify stimulation parameters required to obtain the chosen neural firing patterns. A number of examples illustrate the utility of this method, revealing the spatio-temporal responses for varying numbers of neurons and electrode displacements.
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    A stochastic model of the electrically stimulated nerve designed for the analysis of large-scale population [Abstract]
    Bruce, I. ; Irlicht, L. S. ; White, M. ; O'Leary, S. J. ; Dynes, S. ; Javel, E. ; Clark, Graeme M. ( 1997)
    Accurate models of Auditory Nerve (AN) response to electrical stimulation may aid in the development of speech processing strategies for cochlear implants. Most models of AN response to electrical stimulation utilize deterministic (non-random) description in spite of strong evidence for stochastic (random) activity in physiological data. Inclusion of stochastic activity in complex models of neural response such as the Hodgkin-Huxley equations has proven to be computationally expensive. They are therefore unsuitable at this time for the calculation of large-scale population responses which could be required for the investigation of sound coding in ensembles of nerve fibers, for the explanation or prediction of psychophysical results, or for the development of speech processing strategies for cochlear implants. It is therefore necessary to develop a simpler model of single-fiber response to electrical stimulation which includes stochastic activity.
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    Electrical stimulation of the auditory nerve: prediction psychophysical by a model including stochastic aspects of neural response [Abstracts]
    Bruce, I. ; Irlicht, L. S. ; White, M. ; O'Leary, S. J. ; Clark, Graeme M. ( 1997)
    Accurate models of Auditory Nerve (AN) response to electrical Stimulation may assist with the development of speech processing strategies for cochlear implants. Until recently most models of AN response to electrical stimulation have utilised deterministic (non random) descriptions, in spite of strong evidence for stochastic (random) components of behaviour in the neurophysiological data models of auditory performance using these deterministic descriptions have been unable to predict many important psychophysical phenomena. Can stochastic models improve these predictions.
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    A mathematical model of electrical stimulation of the auditory nerve [Abstract]
    Bruce, I. ; Irlicht, L. S. ; White, M. ; O'Leary, S. J. ; Dynes, S. ; Javel, E. ; Clark, Graeme M. ( 1997)
    Accurate models of Auditory Nerve (AN) response to electrical Stimulation may assist with the development of speech processing strategies for cochlear implants. Until recently most models of AN response to electrical stimulation have utilised deterministic (non random) descriptions, in spite of strong evidence for stochastic (random) components of behaviour in the neurophysiological data. Models of auditory performance using these deterministic descriptions have been unable to predict many important psychophysical phenomena. Can stochastic models improve these predictions.
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    Responses from single units in the dorsal cochlear nucleus to electrical stimulation of the cochlea
    O'Leary, S. J. ; Tong, Y. C. ; Clark, Graeme M. ( 1992)
    To help improve our understanding of how the brain responds to electrical stimulation of the auditory nerve we have examined the responses of dorsal cochlear nucleus (DCN) units to both acoustic stimulation and electrical stimulation of the cochlea. This work extended our previous studies which have compared the responses to electrical and acoustic stimulation In the auditory nerve (Javel et al 1987, Ann. Otol. Rhinol. laryngeal. Suppl. 128, 96:2630) and the ventral cochlear nucleus (Shepherd et al 1988, NIH Contract NO1-NS-72342, 5th Quarterly Progress Report).