Voice onset time encoding in patients with left and right cochlear implants.

Stop-consonant discrimination was investigated in normal-hearing listeners and cochlear-implanted patients (CIP) by recording auditory evoked potentials (AEPs) to /b epsilon/ and /p epsilon/ syllables. This study demonstrates that: (i) AEPs show time-locked components that mimic the temporal structure of the stimuli, indicating that both patients and control subjects encode those syllables according to the temporal cue (voice onset time) characterizing the voiced/voiceless contrast; (ii) the side of implantation does not affect the general structure of AEPs and /b epsilon/-/p epsilon/ discrimination thresholds (measured separately with a psychophysical procedure); (iii) poor time-locking to the syllables' temporal structure is associated with poor discrimination. This suggests that EEG investigation of temporal-processing provides an objective index of speech perception in CIP and could be used in implanted children.