A digital speech processor and various speech encoding strategies for cochlear implants

We distinguish two main categories in the speech decoding strategies: those based on feature extraction and those based on time information of the filtered incoming signal. In the first group only those electrode pairs corresponding to the localisation of the four or more, maximum spectral peaks or the formants of the speech signal are stimulated. The second category is essentially based on the timing information that is included in the filter outputs of the filtered speech signal. The Laura implant has the capability to be programmed to the different decodings-strategies. To understand the potential possibilities the main features of the implant are discussed.