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dc.contributor.authorLinahan, N.en_US
dc.contributor.authorTykocinski, R. K.en_US
dc.contributor.authorShepherd, Robert K.en_US
dc.contributor.authorClark, Graeme M.en_US
dc.date.accessioned2014-05-21T20:01:49Z
dc.date.available2014-05-21T20:01:49Z
dc.date.issued1999en_US
dc.identifier.citationLinahan, N., Tykocinski, R. K., Shepherd, R. K., & Clark, G. M. (1999). Physiological and histopathological effects of chronic monopolar stimulation on the auditory nerve using very high stimulus rates [Abstract]. In Proceedings of the Australian Neuroscience Society, Hobart.en_US
dc.identifier.urihttp://hdl.handle.net/11343/27034
dc.descriptionThis is an abstract of a paper from the Proceedings of the Australian Neuroscience Society 1999 published by Australian Neuroscience Society. This version is reproduced with the permission of publisher.en_US
dc.description.abstractSpeech-processing strategies using high stimulus rates are used in some cochlear implant systems. While some data suggests that electrical stimulation of the auditory nerve at rates of 2000 pps per channel is safe, there is little data concerning higher rates. The present study was designed to evaluate the safety of a rate of 5000 pps per channel. Under anaesthesia, (ketamine (20 mg/kg. i.v.) and xylazine (3.8 mg/kg. i.v.)), four normal hearing cats were bilaterally implanted with a three channel platinum (Pt) scala tympani electrode array and a return Pt-electrode placed within the temporalis muscle. Each animal was stimulated unilaterally for durations of up to 2700 h using 25μגs per phase charge-balanced biphasic current pulses. The stimuli were delivered at 5000 pps per channel at mid-dynamic range intensities. Acoustically-evoked auditory brainstem responses (ABRs) were recorded during the stimulation regime to monitor the animals' residual hearing. Electrically-evoked auditory brainstem responses (EABRs) were periodically recorded to monitor the status of the auditory nerve and to ensure stimulus intensity remained above threshold. ABRs typically showed poor recovery in the stimulated ear. Longitudinal EABRs recorded from all animals remained relatively stable for the duration of stimulation. Electrode impedances were calculated from daily monitoring of current and voltage waveforms. Two animals that exhibited the highest electrode impedance throughout the duration of stimulation were found to have significant amounts of new bone growth and fibrous tissue in the basal region of the cochlea. However, as one of these animals showed a similar response in the contralateral, unstimulated, implanted cochlea, this response can not be attributed to electrical stimulation per se. There was no statistically significant difference in spiral ganglion cell density in the stimulated cochleae when compared to corresponding regions in controls (p?0.2, Mann-Whitney Rank. Sum Test). These initial results indicate that chronic monopolar stimulation of the cochlea at a rate of 5000 pps per channel does not have an adverse effect on spiral ganglion cell density.en_US
dc.relation.ispartofScientific publications, vol.11, 1998-1999, no.1205en_US
dc.subjectotolaryngologyen_US
dc.subjectbrainstemen_US
dc.subjectcochlear implant systemsen_US
dc.subjectABRen_US
dc.subjectEABRen_US
dc.titlePhysiological and histopathological effects of chronic monopolar stimulation on the auditory nerve using very high stimulus rates [Abstract]en_US
dc.typeConference Itemen_US
melbourne.source.titleProceedings of the Australian Neuroscience Societyen_US
melbourne.source.month31 January - 3 Februaryen_US
melbourne.source.volume10en_US
melbourne.source.pages181en_US
melbourne.source.locationconferenceHobarten_US
dc.description.sourcedateconference31 January - 3 Februaryen_US
melbourne.elementsidNA
melbourne.contributor.authorClark, Graeme
melbourne.contributor.authorShepherd, Robert
melbourne.contributor.authorXu, Jin
melbourne.accessrightsOpen Access


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