The identification of consonants and vowels by cochlear implant patients using a 6-channel continuous interleaved sampling processor and by normal- hearing subjects using simulations of processors with two to nine channels

Objective: To compare the vowel and consonant identification ability of cochlear implant patients using a 6-channel continuous interleaved sampling (CIS) processor and of normal-hearing subjects using simulations of processors with two to nine channels. Design: Subjects, 10 normal-hearing listeners and seven cochlear implant patients, were presented synthetic vowels in /bVt/ context, natural vowels produced by men, women, and girls in /hVd/ context, and consonants in /aCa/ context for identification. Stimuli for the normal-hearing subjects were pre-processed through simulations of implant processors with two to nine channels and were output as the sum of sinusoids at the center frequencies of the analysis filters. Results: Five implant patients' scores fell within the range of normal performance with a 6-channel processor when the patients were tested with synthetic vowels. Four patients' scores fell within the range of normal with a 6-channel processor when the patients were tested with multitalker vowels. Five patients' scores fell within the range of normal for a 6-channel processor for the consonant feature 'place of articulation.' Conclusion: Signal processing technology for cochlear implants has matured sufficiently to allow some patients who use CIS processors and a small number of monopolar electrodes to achieve scores on tests of speech identification that are within the range of scores established by normal-hearing subjects listening to speech processed through a small number of channels.