Deficits of perceived spatial separation induced prepulse inhibition in patients with schizophrenia: relationships to symptoms and neurocognition

BACKGROUND Prepulse inhibition (PPI) and attention were impaired, which may cause psychotic symptoms and (or) hinder the cognitive functions in schizophrenia. However, due to the measurement methods of PPI, findings about the relationship between PPI and clinical symptoms, cognitive performances have been equivocal. METHODS Seventy-five schizophrenia patients (SZ) and 50 healthy controls (HC) were assessed in a modified acoustic PPI paradigm, named perceived spatial separation-induced PPI (PSS-PPI), compared to perceived spatial co-location PPI (PSC-PPI) with inter-stimulus interval (ISI) of 120 ms. Repeatable Battery for the Assessment of Neuropsychological Status and the Stroop Color-Word Test were administered to all subjects. RESULTS Significant decrease in the modified PPI was found in the patients as compared to the controls, and effect sizes (Cohen'd) for patients vs. HCs % PPI levels achieved a significant level (PSC-PPI d = 0.84, PSS-PPI d = 1.27). A logistic regression model based on PSS-PPI significantly represented the diagnostic grouping (χ2= 29.3; p < 0 .001), with 85.2% area under ROC curve in predicting group membership. In addition, patients exhibited deficits in neurocognition. Among patients of "non-remission", after controlling for gender, age, education, duration, recurrence times, onset age, cigarettes per day and chlorpromazine equivalent dosage, PSS-PPI levels were associated with positive and negative symptoms, PANSS total and thought disorder (P1, P6, P7, N5, N7, G9). In multiple linear regression analyses, male and higher attention scores contributed to better PSC-PPI and PSS-PPI in controls group, while larger amount of smoke and longer word-color interfere time contributed to poor PSS-PPI. In patients' group, higher education and attention scores contributed to better PSS-PPI, while repeated relapse contributed to poor PSS-PPI. CONCLUSIONS The acoustic perceived spatial separation-induced PPIs may bring to light the psychopathological symptoms, especially for thought disorder, and the mechanism(s) of the novel PPI paradigm was associated with attention function.