Abstract: Objective  To explore the neurophysiological signatures of auditory event-related potentials (AERP) during propofol-induced graded sedation depths,  and their correlations with sedation levels and behavioral responsiveness, and further to evaluate the feasibility of AERP components as potential biomarkers for quantifying consciousness states. Methods  An auditory Oddball paradigm was used to evoke AERP responses in healthy volunteers under propofol-induced graded sedation. Linear mixed model was applied to explore the relationships between the mean amplitudes of AERP components ［mismatch negativity(MMN); P300］and both sedation-induced conscious states ［Modified Observer's Assessment of Alertness/sedation Scale(MOAA/S) scores］ and behavioral performance (response accuracy). Results  Twenty-two healthy volunteers were included. Data analysis revealed significant negative correlations between the mean amplitudes of MMN components ［MMN -Dev:β=-0.62(-2.70--0.07)，P=0.04; MMN-Nov：β=-0.15(-0.27--0.03)，P=0.02］ and MOAA/S scores during propofol sedation. Novel stimulus-evoked MMN amplitudes also correlated with response accuracy ［MMN-Nov：β=-5.08(-7.78--2.37)，P<0.01］. There was a weak positive correlation between novel stimulus-evoked P300 amplitudes and MOAA/S scores ［β=0.16(0.04-0.39), P=0.04］, however, the correlation was no significant  difference  after adjusting for confounding factors including age, education level, and cognitive level. Conclusion  The mean amplitude of MMN component elicited during auditory tasks was correlated with conscious states and behavioral accuracy under propofol-induced graded sedation. MMN holds promise as a potential neurophysiological indicator for quantifying conscious states or behavioral responsiveness during sedation.

Key words: general anesthesia, propofol, auditory event-related potential, mismatch negativity, P300, sedation depths