Spatial release from masking in bilateral cochlear implant users listening to the temporal limits encoder strategy

Binaural hearing benefits with bilateral cochlear implants (CI) are usually smaller than with normal hearing (NH) in the same tasks. This gap in performance has typically been attributed to a lack of coordinated stimulation between ears and the high stimulation rates used in clinical processors. These factors hinder sensitivity to interaural timing differences (ITDs); an important binaural cue for NH listeners. The Temporal Limits Encoder (TLE) strategy was originally designed to encode unilateral low-frequency temporal fine structure pitch cues into the signal envelope of CIs. However, TLE also lowers the stimulation rate on some channels which may potentially provide useable ITD cues. Here, we measured spatial release from masking (SRM) in bilateral CI users listening to TLE vs Advanced Combinational Encoder (ACE) strategy to determine if TLE provides a benefit. The CCiMobile research platform was used for testing. Results from eight listeners showed comparable word recognition performance in quiet and co-located conditions for TLE and ACE, even with a short acclimatization period with TLE. In the spatially-separated condition, performance across the group was more similar with TLE than ACE, and more listeners showed SRM. These results indicate that TLE has the potential for improving binaural hearing benefits for CI users.