Cochlear implant codes and speech perception in the profoundly deaf

Abstract

Cochlear implants are coming into widespread use as prostheses for profoundly deaf patients suffering from sensorineural deafness. Such patients can detect sounds when the implant electrically stimulates their remaining peripheral auditory nervous system. But useful speech recognition has not yet been achieved with either single- or multiple-channel cochlear implants. Because cochlear implants are essentially artificial receptors, the prosthetic signal provided by such implants must be coded in a form that contains the essential attributes of the sensory codes used by natural receptors. Sensory coding studies of natural receptors have indicated that the sensory code is task dependent. In particular, these studies have indicated that the sensory code for pattern recognition is the integral of the temporally dispersed receptor signal. These natural receptor data suggest that speech recognition in the profoundly deaf may be improved by incorporating an appropriate degree of temporal dispersion into the design of cochlear prostheses.