In this paper, we evaluate the performance of six intrusive objective measures as intelligibility predictors of degraded speech for cochlear implant (CI) users. Three practical environmental degradation scenarios are considered: reverberation alone, additive noise alone, and noise-plus-reverberation. A subjective intelligibility test was performed with eleven cochlear implant users and objective measures were evaluated using three performance metrics: Pearson, Spearman rank, and sigmoid-fitted correlation coefficients. It was observed that existing metrics performed well in the noise-alone scenarios, but obtained lower performance in the reverberation-alone scenario and in many cases, unacceptable results in the noise-plus-reverberation scenario. It is concluded that further work is still needed in order to accurately predict speech intelligibility ratings for CI users, particularly in environments corrupted by reverberation.

Index Terms: Objective Measures, Speech Intelligibility, Reverberation, Noise, Cochlear Implants