Influence of filtering and compression on modelled auditory nerve responses to electrical stimulation

Sound processing in cochlear implants mainly consists of filtering and non-linear compression, and determines the representation of spectro-temporal features of speech in the electrical stimulation patterns. The influence of filtering and compression on auditory nerve responses to electrical stimulation was studied with single-formant stimuli (SFS) as an input. A simple model was used to generate responses in ensembles of auditory nerve fibres. Temporal features of modelled responses were compared with those of SFS, electrical stimulation patterns and measured responses to acoustic SFS. It turned out that the properties of stimulation pattern and neural response ate different, while filtering and compression strongly influence these differences. It is argued that in research for optimal speech intelligibility with cochlear implants, aspects of both stimulation patterns and neural responses must be regarded.