The identification of speech in noise by cochlear implant patients and normal-hearing listeners using 6-channel signal processors

Objective: To compare the recognition of vowels and sentences in noise by c ochIear implant patients using a g-channel, continuous interleaved sampling (CIS) processor and by normal-hearing subjects listening to speech process ed in the manner of the implant processor and output as six amplitude-modul ated sine waves. Design: Subjects, 11 normal-hearing listeners and 7 cochlear implant patien ts, were presented natural vowels produced by men, women, and girls in /hVd / context and sentences from the Hearing In Noise Test (HINT) lists at +15, +10, and +5 dB signal to noise ratio (SNR) for identification. Stimuli for the normal-hearing subjects were preprocessed through a simulation of a 6- channel implant processor and were output as the sum of sinusoids at the ce nter frequencies of the analysis filters. Results: For the multitalker vowels, four of the seven patients achieved sc ores within +/-1 standard deviation of the mean for normal-hearing listener s at +15 and +10 dB SNR. At the +5 dB SNR three patients achieved scores wi thin +/-1 standard deviation of the mean for the normal-hearing listeners. For the HINT sentences, four of seven patients achieved scores within +/-1 standard deviation of the mean for the normal-hearing listeners at +/-15 dB and at +10 dB SNR and two achieved scores within that range at +5 dB SNR. Conclusion: Our results extend the range of stimulus conditions, from quiet to modest amounts of noise, in which the CIS strategy allows the best perf orming patients to extract most, if not all, of the information available t o normal-hearing subjects listening to speech processed into six channels.