Fig. 2.
Speech intelligibility for five BCI listeners in three conditions. In the “diotic” condition, no binaural cues were applied to either the target or the masker. In the “natural” condition, binaural cues were applied, which included the ILD-by-frequency function shown in Figure 1, and a whole-waveform ITD of 600 μs. In the “enhanced” condition, the stimulus mixture created in the natural condition was subjected to the ITD-to-ILD algorithm, which applied low-frequency ILD cues based on the instantaneous ITD information. The difference in performance between the diotic and natural conditions represents the SRM that the participants would receive typically. The difference between the natural and enhanced conditions represents the additional SRM provided by the binaural enhancement. BCI indicates bilateral cochlear implant; ILD, interaural differences of levels; ITD, interaural differences of time; SRM, spatial release from masking.