Reduction of the stimulation timing mismatch in bimodal listeners – Effect on sound localization and spatial release from masking

Previous work has shown that the sound localization ability of bimodal listeners provided with a cochlear implant and a hearing aid can be improved when the constant interaural time delay (timing mismatch - TM) is reduced. The TM is caused by differences in processing delays of the hearing devices and differences in stimulation sites. When it comes to spatial release from masking (SRM), our own measurements have shown that the temporal alignment of the ear signals is also relevant for speech understanding in noise, when speech and noise sources are not co-located. SRM is as large as 8-9 dB in NH listeners without a temporal mismatch. As soon as a TM is introduced, SRM decreases. At 7 ms (typical TM of bimodal listeners) about 4 dB remain. in contrast, our recent findings in bimodal listeners show that SRM is