Follow-up of N400 in the Rehabilitation of First-episode Schizophrenia

Background: The N400 component of event-related potentials (ERP) has recently drawn widespread attention at home and abroad. This study was to explore the relationship between N400 changes and risperidone treatment and rehabilitation in first-episode schizophrenia (FES). Methods: ERP component N400 was recorded by Guangzhou Runjie WJ-1 ERP instruments, in 58 FES before and 6 months, 15 months after risperidone treatment, and in 62 normal controls. The patients' syndromes were assessed by Positive and Negative Syndrome Scale (PANSS). And the stimuli are Chinese sentences with matching (congruent) or mismatching (incongruent) ending words. Results: N400 latencies were prolonged, and amplitudes were decreased in Cz, Pz, Fz, C3, C4, in FES compared with in NC, before treatment. The prolonged N400 latencies and decreased amplitudes were negatively correlated with the patients' positive scale and total scale of PANSS. There are significant differences of N400 amplitudes and latencies in 6 months and 15 months follow-up after treatment. Before treatment, 6 months and 15 months after treatment, N400 latencies are 446 +/- 35 ms, 440 +/- 37 ms, 414 +/- 31 ms (F = 9.72, P < 0.01) in incongruent situation; N400 amplitudes are 5.2 +/- 4.6 mu V, 5.7 +/- 4.8 mu V, 7.3 +/- 5.0 mu V (F = 2.06, P > 0.05) in congruent situation, and 8.5 +/- 5.9 mu V, 10.1 +/- 5.0 mu V, 11.9 +/- 7.0 mu V (F = 3.697, P < 0.05) in incongruent situation. Conclusions: N400 could be used to predict the effects of treatment of schizophrenia to some degree. The linguistic and cognitive impairment in schizophrenia can be improved by antipsychotic drugs.