Speech Intelligibility evaluation in the presence of speech masker of cochlear implant in a reverberant room

In this report, we investigated the performance of a cochlear implant (CI) in a reverberant room with the presence of a competing speech masker. We compared Short-Time Objective Intelligibility (STOI) and Perceptual Speech Quality (PESQ) to represent the objective, to percent correct word (PCW) and Mean Opinion Score (MOS) as subjective evaluations, respectively. The target and the masker speech were convoluted with 0.4- and 0.7-s reverberation time, respectively, then processed with a 14-channel vocoder. We set the target to the masker 5dB and 0 dB SNR. We simulated two well-known techniques, namely CIS and SPEAK processors. Ten normal-hearing paid subjects were participated to evaluate the performance in clean, reverberant with no masker and reverberant with masker. The results showed that performance degraded significantly as the reverberation duration increased. Furthermore, the presence of a masker to a target speech in a reverberant room worsened all the evaluated performances compared to the reverberant alone. The results suggested that further investigation is required to reduce the masker effect to improve CI intelligibility.