Coding of received audio signals and the resulting application of electrical stimuli applied to electrodes used in a cochlear implant system are disclosed together with a method of fitting this new coding strategy. One of the aims is to improve place specific stimulation representing pitch by applying near threshold electrical stimuli with limited and focussed excitation fields. A range of stimulation rates and a minimal range of current levels above threshold are used for creation of a dynamic loudness percept for a cochlear implant recipient. Another aim is to disclose a coding scheme based on a model of physiological measures (i.e. refractoriness, adaptation, spread of activation field, spatiotemporal acoustical cochlear activation patterns and spontaneous activity) to estimate the proportions of available excitable auditory neurons close to the electrodes available for stimulation. The spectral bands formed from the pre-processing of incoming audio signals are weighted by these proportions of excitability to control place, timing, rate and current level of electrical stimuli applied to the electrodes available in the array.
SOUND PROCESSING METHOD AND SYSTEM