M70. Abnormal P300 Novel and P300 Oddball Event Related Potentials in Persons at Clinical High Risk for Psychosis in Shanghai

摘要

>Background: Auditory P300 oddball and P300 novel components index working memory operations and salience, respectively, and are regarded as biomarkers of neurocognitive changes associated with schizophrenia. Abnormalities in P300-oddball and P300-novel event related potentials (ERPs) have been found in both chronic and first episode schizophrenia. Much less is known whether abnormalities exist in individuals at clinical high risk for psychosis (CHR), whether they are associated with conversion to psychosis, and whether they are observed in different ethnic groups around the world. We report data from the “Shanghai At Risk for Psychosis (SHARP)” study conducted at the Shanghai Mental Health Center (SMHC). >Methods: CHR status was determined with the Structured Interview for Prodromal Syndromes (SIPS) at participants’ first visit to the SMHC. A cohort of 300 CHR and 150 Healthy Control (HC) participants was recruited between 2012 and 2015, and will be followed up for at least 1 year. To date, EEG was recorded using BrainAmp system in age-matched groups of 15 CHR converters (CHR-C), 120 CHR non-converters (CHR-NC) and 77 healthy controls (HC) using P300-oddball and P300-novel paradigms and standard methods to define CHR and conversion. P300 amplitude and latency to rare tones was analyzed from Cz, CPZ and Pz. P300 amplitude and latency to novel tones was analyzed from Fz, FCZ, and Cz. >Results: P300-oddball: Amplitude: The groups differed significantly (P = .02) with lower P300 amplitude in CHR-C (P = .01) and CHR-NC (P = .04) vs HC, with no significant differences between CHR groups. Latency: The groups differed (P = .01) with longer latency in CHR-C relative to both CHR-NC (P = .02) and HC (P = .003), with no significant differences between CHR-NC and HC. P300-novel: Amplitude: The groups differed (P = .003) with both CHR-C (P = .002) and CHR-NC (P = .02) having lower P300 novel amplitudes than HC. Importantly CHR-C showed lower amplitudes than CHR-NC (P = .047). Latency: No group differences. >Conclusion: These results suggest important differences in how WM and salience processes are impacted by CHR-related changes. There was a gradient of abnormality in which CHR-C had the most abnormal ERP responses, suggesting ERPs could be a biomarker for conversion. Distinctions between groups P300-novel amplitude, P300-oddball amplitude and latencies will be discussed. Analysis of the complete baseline data will be carried out after follow-ups are complete in January, 2017.