An interaural electrode pairing clinical research system for bilateral cochlear implants

Bilateral cochlear implants (BiCIs) have succeeded in improving the spatial hearing performance of bilateral CI users, albeit with considerable variability across implantees. Limited success can be caused by an interaural mismatch of the place-of-stimulation that arises from electrode arrays being inserted at different depths in each cochlea. In comparison to subjective pairing methods such as pitch matching, one promising objective measure based on electrically evoked auditory brainstem responses (EABR), the binaural interaction component (BIC), could be used to optimize the interaural electrode pairing (IEP) in BiCIs. Matched interaural electrodes are expected to facilitate binaural functions such as binaural fusion, localization, or detection of signals in noise. An IEP system, currently under development for clinical research, is proposed. The system offers subjective and objective IEP methods for BiCI: a psychoacoustic test module for pitch ranking and interaural pulse time difference (IPTD) sensitivity, and a binaural and monaural EABR recording module to derive the BIC. Psychoacoustic and IEP measures from two implantees are presented.