175. A component-level reassessment of auditory mismatch negativity and P3a deficits of schizophrenia
Abstract
Abstract Background Auditory mismatch negativity (MMN) deficit and P3a are robust neurophysiological biomarkers of schizophrenia. These event-related potentials (ERPs) are suggested to involve several neuronal processes, including adaptation to repeated stimuli, differential response to different stimuli, and deviance detection. By combining the oddball and many-standards paradigms, the neuronal mechanisms of the ERP markers could be disentangled. Aims & Objectives The study aimed to explore whether schizophrenia is associated with deficits in different neuronal mechanisms components underlying MMN and P3a. Method This is a case-control study that enrolled 34 patients with schizophrenia and 33 matched healthy controls. All participants underwent electroencephalogram experiments using both the auditory oddball paradigm (50-ms standard tones, probability 0.9; 100-ms deviant tones, probability 0.1) which elicited MMN and P3a, and the many-standards paradigm (10 different tone durations presented with equal probability) from which the adaptation, tone difference, and deviance detection components of MMN and P3a can be derived. The ERPs and components were compared between groups. The relationship between ERPs and their corresponding components was explored. Results Significantly reduced mean MMN and mean P3a amplitudes were observed in schizophrenia patients. All components of MMN and only the deviance detection component of P3a were impaired in the schizophrenia group. MMN, P3a, and their components were not associated with symptom severity, function, or doses of antipsychotic agents. The adaptation and deviance detection components were correlated with MMN and P3a, and a moderating effect of schizophrenia on the correlation between the deviance detection component and MMN was observed (schizophrenia: R2 = 0.164, control: R2 = 0.413, p <.001). Discussion & Conclusions Although a previous study suggested only the deviance detection component of MMN was impaired in schizophrenia, the current study found deficits in all three components. Altered deviance detection still deserves further investigations since its relationship with MMN was differentially attenuated in schizophrenia, and it was the only component of P3a that was impaired.