Graeme Clark Collection

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1997 - 1999 2 2000 - 2004 2
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Start date: 1997 × Subject: cochlear implants × Subject: electrical stimulation × Subject: speech processing ×

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Now showing 1 - 4 of 4
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    Inner ear implants
    Clark, Graeme M. (Dekker, 2004)
    The cochlear implant is an electronic device that brings useful hearing to severely to profoundly deaf people through multiple-channel electrical stimulation of the auditory nerves in the inner ear. This is required if their inner ears are so badly damaged by injury and disease, or so inadequately developed, that they cannot provide sufficient hearing for communication, even when the sound is amplified with a hearing aid. By stimulating the nerve directly with patterns of electrical pulses, the implant bypasses the normal function of the sense organ of hearing in the inner ear to partially reproduce the coding of sound. It consists of a wearable speech processor that picks up sound with a microphone, analyzes the signal, and then sends it by radio waves to the implanted receiver stimulator, which decodes the message and stimulates the electrode wires inserted into the inner ear.
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    Research advances for cochlear implants
    Clark, Graeme M. ( 1998)
    Abstract not available due to copyright.
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    Physiological and histopathological effects of chronic monopolar high rate stimulation on the auditory nerve
    TYKOCINSKI, MICHAEL ; Linahan, N. ; Shepherd, R. K. ; Clark, Graeme M. ( 2000)
    Speech processing strategies based on high rate electrical stimulation have been associated with improvements in speech perception among cochlear implant users. The present study was designed to evaluate the electrophysiological and histopathological effects of long-term intracochlear monopolar stimulation at the maximum stimulus rate of the current Nucleus Cochlear implant system (14493 pulses/s) as part of our ongoing investigations of safety issues associated with cochlear implants
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    Advances in cochlear implant speech processing [Abstract]
    Clark, Graeme M. ( 1997)
    Our early research emphasized there was a restriction on the amount of speech and other acoustic information that could be transmitted to the nervous system by electrical stimulation of the auditory nerve. It also showed the need to use multiple-channel stimulation, and minimize channel interaction. As a result our research over the last 30 years has been directed towards optimizing the information presented to the auditory nervous system. This has involved extracting the energy of the first and second formants (FO/F2-WSP II; FO/FI/F2-WSP III; Multipeak-MSP) as well as the outputs of high band pass fixed filters (Multipeak - MSP) and coding these outputs as cochlear place of stimulation. The voicing frequency was coded as rate of stimulation. Our most recent speech processing strategy (SPEAK) extracts a specified number of .maximal outputs from a series of band pass filters, rather than selecting the peaks of energy which was the case with the other strategies. The voltages from the maximal outputs are used to stimulate appropriate electrodes on a place coding basis. The stimuli are presented at a constant stimulus rate to reduce channel interaction. Voicing is conveyed as amplitude variations.