A physiological correlate of electroacoustic pitch matching in cochlear implant users with residual hearing

One challenge facing postlingually deafened cochlear implant (CI) users is the frequency mismatch between the incoming acoustic signal and the characteristic frequency of the electrically stimulated neurons. Current CI will require extensive effort in fine tuning to help users to adapt to this mismatch. A recent work [1] attempts to address this issue using a closed-loop CI system with evoked potentials as feedback. However, the stimulus artifact produced by CI and the limitation of subcortical responses in assessing speech perception are yet to resolve. In this paper we present our proposed cortical auditory evoked potential (AEP) evolved from a study [2] that addresses this mismatch. We describe the background then the experiments involved in the development of the AEP with recordings from 3 normal hearing (NH) listeners and 2 CI users. We also discuss how the AEP could be used in a closed-loop CI system.