P300 response to tones and speech sounds after cochlear implant: a case report.

P300 potentials evoked by tones and spoken words were recorded from a 20-year-old man with a House-3M single-channel cochlear implant. Three months after cochlear implantation, there was a slight appearance of P300 response to both pure-tone stimuli and spoken-word stimuli; 6 months later, clearly identifiable P300 response to both pure-tone stimuli and spoken-word stimuli were obtained. These results are consistent with an encoding improvement for re-establishment of information processing after auditory rehabilitation.