[Prepulse inhibition of startle reflex in schizophrenics and healthy adults]

To evaluate the characteristics of sensory gating inhibition and variation of schizophrenia with both prepulse inhibition (PPI) and P50.

The PPI of startle reflex and P50 were tested by an event-related potential (ERP) recorder in 82 first episode schizophrenics (FES) recruited from September 2007 to February 2014 at Shanghai Mental Health Hospital and 78 healthy controls (NC) from hospital staffs and local residents for the same period. All patients fulfilled the evaluation of PPI with strong stimulus alone and strong + weak stimulus paradigm, P50 with conditioning (S1)-testing (S2) paradigm. The psychotic symptoms were assessed with Positive and Negative Syndrome Scale (PANSS).

(1) Compared with control group, schizophrenia group had increased P(L) (NC: (89 ± 14) ms, FES: (97 ± 17) ms, P < 0.05) and PPL, decreased amplitude (NC: (92 ± 21) ms, (24 ± 14) µV, FSZ: (96 ± 20) ms, (41 ± 29) µV, P < 0.05, 0.01), lower PPI inhibition ratio (NC: (67 ± 32)%, FSZ: (41 ± 37)%, P < 0.05). (2) Compared with NC group, there were increased S2 amplitude [NC: (3 ± 2) µV vs FES: (5 ± 3) µV, P < 0.05] and ratio of S2/S1 amplitude [(43 ± 22) % vs (82 ± 41)%, P < 0.05] in schizophrenia group. And P50 inhibition decreased significantly.

Schizophrenics have both PPI and P50 impairments. And a combination of PPI inhibition ratio and S2/S1 (P50) may be a better electrocerebrophysiological index for schizophrenia.