The Continuous Interleaved Sampling (CIS) strategy is recognized as providing significant improvements in performance using multiple channel cochlear implants. The proposed investigation would focus on the development of new signal processing strategies which could help improve the performance of the CIS processor. This study proposes optimization strategies which operate in closed loop configuration to select stimulation amplitudes for each channel for the processor. The principle of selection is such that the difference between the stimulating (electrical) pattern and the acoustic pattern is minimized. The error criteria that are being tested were selected based on perceptual results. The first phase of work involves the design and construction of a laboratory speech processor. Initially, the CIS strategy will be implemented on this processor and tested on cochlear implant patients with percutaneous connectors. The speech processor will be modified in the second stage to include new strategies, which will also be tested on the cochlear implant patients. Two general strategies are proposed, one that is aimed at better waveform matching, and one that is aimed at better spectral matching. The strategies will also be simulated and tested on normal-hearing subjects. The results of these studies will be compared to determine which type of information, temporal or spectral, is more important for cochlear prosthesis.
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