Cochlear implant artefact reduction in electroencephalography data obtained with the auditory oddball paradigm and stimuli with differing envelopes

Cortical auditory evoked potentials (CAEPs) are a popular neurophysiological measure in the assessment of auditory processing capabilities. Research evidence suggests that CAEPs may be employed to assess auditory discrimination abilities, which is of particular interest in monitoring clinical rehabilitation outcomes in cochlear implant (CI) users. However, the electrical artefact from CI stimulation poses a challenge for the signal analysis. Numerous artefact reduction procedures have been proposed, many of which are computationally costly or subjectively biased. This study investigated a simplified approach to CI artefact reduction based on subtraction, which was enabled by introducing an enhanced auditory oddball paradigm. Outcome CAEPs were compared to the gold-standard artefact reduction based on independent component analysis (ICA). Grand average difference potentials showed successful artefact reduction for both artefact rejection algorithms in the enhanced oddball paradigm. With the enhanced oddball paradigm, measured peak-to-peak amplitudes were significantly larger with subtraction-based processing than for ICA-based processing, suggesting that the removed independent components not only contained artefact, but also neural activity of interest.