Three-year follow up of event-related potentials PPI, P50 and Color map of N400 during the rehabilitation of first episode schizophrenia patients

Abstract

To investigate the relationship between the variations of event-related potentials (ERP) and clinical symptoms and treatment in first episode schizophrenia patients. The ERP (P50, color map of N400 and prepulse inhibition of the startle reflex (PPI) ) were tested in 85 first episode schizophrenia (FES) patients and 78 normal controls (NC), and followed-up at 1, 2 and 3 years after treatment in FES. Positive and negative symptom scale (PANSS) was used to evaluate the psychotic symptoms of patients. (1) Compared with NC, FES showed decreased PPI% (41% ± 37% vs 68% ± 42%, P < 0.001), increased P50 S2/S1(87 ± 41 vs 51 ± 47, P < 0.001), prolonged N400 latency and decreased N400 amplitudes (P < 0.05 - 0.01 ). ( 2) Significant correlations were found between variations of color map of N400 latencies and general scores of PANSS (r = 0.321, P = 0.042), N400 amplitude and positive symptom scores (r = -0.437, P = 0.008) and total scores of PANSS (r = -0.392, P = 0.023), but the variations of PPI and P50 latencies and amplitudes did not show significant correlation with the positive symptom scores and total scores of PANSS. (3) The color map of N400 latencies and amplitudes in FES group showed significant difference (P < 0.05) but the major indexes of PPI and P50 did not show significant difference (P > 0.05) among the 1, 2 and 3 years' follow-up after treatment. This follow-up study suggests that the variations of PPI and P50 is probably a trait marker of FES, and the variations of color map of N400 might be a status marker of FES.