[N400 changes elicited by Chinese sentences in first episode schizophrenia]

To explore N400 changes elicited by Chinese sentences ending with matching (congruent) or mismatching (incongruent) words in first episode schizophrenia.

ERP (event-related potentials) component N400 were recorded by an ERP device in 56 first episode schizophrenia (FES) and 62 normal controls (NC) according to a paradigm of Chinese sentences ending with matching or mismatching words.

(1) Latencies: compared with NC, FES showed prolonged N400 latencies in five areas at pre-treatment: in Cz. The latencies were (358 ms ± 32 ms vs 394 ms ± 45 ms, P < 0.01) in congruent and (410 ms ± 29 ms vs 446 ms ± 35 ms, P < 0.01) in incongruent situation. And so did in Fz, Pz, C3 and C4; (2) amplitudes: compared with NC, FES also showed smaller N400 amplitudes in five areas at pre-treatment. The amplitudes were (8.6 µV ± 5.1 µV vs 5.2 µV ± 4.6 µV, P < 0.01) in congruent and (13.4 µV ± 6.7 µV vs 8.5 µV ± 5.9 µV, P < 0.01) in incongruent situation. And so did in Fz, Pz, C3 and C4; (3) the prolonged N400 latencies and decreased amplitudes were negatively correlated with the patients' positive scale and total scale of PANSS.

With clear priming effect in first episode schizophrenia, Chinese sentences are suitable stimuli in N400 experiment. They may be used for further study of neural mechanism and early diagnosis of schizophrenia.