Wavelet Scattering Transform for Variability Reduction in Cortical Potentials Evoked by Pitch Matched Electro-acoustic Stimulation in Unilateral Cochlear Implant Patients

Cochlear implant (CI) restores the hearing sensation in profoundly deafen patients by directly stimulating auditory nerve with electric pulses using an array of tonotopically inserted electrodes. Basal electrodes stimulate in response to high input frequencies while apical electrodes stimulate to low input frequencies. The problem with this electrical stimulation, particularly in unilaterally implanted users who has residual hearing in the contra-lateral ear, lies in the frequency mismatch between characteristic frequency of auditory nerve and input signal. In this paper, we revisit our previously proposed mechanism for tuning intra-cochlear electrode to its pitch matched frequency using a single channel EEG [1]. We apply the wavelet scattering transform to extract a deformation invariant from the EEG signal recorded from each of 10 CI subjects when they were listening to pitch matched electro-acoustic stimulation. Results show that the wavelet scattering transform is able to capture the variability introduced by different subjects, and a more robust alternative to reveal the underlying neuro-physiological responses to this perceptual event.