Characteristics of stimulus artifacts in EEG recordings induced by electrical stimulation of cochlear implants

Cortical auditory evoked potentials (CAEPs) are frequently used to detect the maturational status of the central auditory system in both healthy persons and cochlear implant listeners. However, with cochlear implant patients, the CAEP is partly or completely submerged in stimulus artifacts induced by current stimulation, making it difficult to faithfully detect auditory evoked potentials with cochlear implants. The aim of this study was to determine if a systematic relationship exists between the artifacts and cochlear implant fitting parameters using speech-like or tone stimuli. Chicken carcus was used as an experimental model to record stimulus artifacts at various implant settings, e.g. monopolar/bipolar stimulation, pulse width, and most comfortable level. The influence of the implant parameter variation on stimulus artifacts was systematically studied. The results of this study could potentially provide useful information for developing methods of eliminating stimulus artifacts in EEG recordings with cochlear implant patients.