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Title: Evaluation of focused multipolar stimulation for cochlear implants in acutely deafened cats
Authors: George, Shefin
Wise, Andrew
Shivdasani, Mohit
Shepherd, Robert
Fallon, James
Keywords: Cochlear implant
Electrical stimulation
Multipolar stimulation
Current focusing
Inferior colliculus
Issue Date: Nov-2014
Publisher: IOP Publishing
Citation: George, S. S., A. K. Wise, M. N. Shivdasani, R. K. Shepherd and J. B. Fallon (2014). Evaluation of focused multipolar stimulation for cochlear implants in acutely deafened cats. Journal of Neural Engineering 11(6): 065003.
Abstract: OBJECTIVE: The conductive nature of the fluids and tissues of the cochlea can lead to broad activation of spiral ganglion neurons using contemporary cochlear implant stimulation configurations such as monopolar (MP) stimulation. The relatively poor spatial selectivity is thought to limit implant performance, particularly in noisy environments. Several current focusing techniques have been proposed to reduce the spread of activation with the aim towards achieving improved clinical performance. APPROACH: The present research evaluated the efficacy of focused multipolar (FMP) stimulation, a relatively new focusing technique in the cochlea, and compared its efficacy to both MP stimulation and tripolar (TP) stimulation. The spread of neural activity across the inferior colliculus (IC), measured by recording the spatial tuning curve, was used as a measure of spatial selectivity. Adult cats (n = 6) were acutely deafened and implanted with an intracochlear electrode array before multi-unit responses were recorded across the cochleotopic gradient of the contralateral IC. Recordings were made in response to acoustic and electrical stimulation using the MP, TP and FMP configurations. MAIN RESULTS: FMP and TP stimulation resulted in greater spatial selectivity than MP stimulation. However, thresholds were significantly higher (p < 0.001) for FMP and TP stimulation compared to MP stimulation. There were no differences found in spatial selectivity and threshold between FMP and TP stimulation. SIGNIFICANCE: The greater spatial selectivity of FMP and TP stimulation would be expected to result in improved clinical performance. However, further research will be required to demonstrate the efficacy of these modes of stimulation after longer durations of deafness.
URI: http://repository.bionicsinstitute.org:8080/handle/123456789/140
Appears in Collections:Bionic Hearing Research Publications

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