Association of cognitive and P50 suppression deficits in chronic patients with schizophrenia

Cognitive deficits are core symptoms of schizophrenia; however, their pathophysiological mechanisms are still unclear. A sensory gating deficit, as reflected by P50 suppression, has been repeatedly shown in schizophrenia patients, which may be associated with cognitive deficits in this disorder. The present study was to examine the relationship between the P50 suppression and cognitive deficits in patients with schizophrenia, which is still under-investigated.

We recruited 38 chronic schizophrenia patients and 32 matched healthy controls, and assessed their cognition with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and P50 suppression with the electroencephalography system.

The total and its 4 index scores (all p < 0.05) except for the visuospatial/ constructional index of RBANS were significantly lower in patients compared with healthy controls. However, only the language and attention passed Bonferroni corrections. Patients displayed a significantly higher P50 ratio, higher S2 amplitude, and lower S1 amplitude (all p < 0.05) than healthy controls. Interestingly, only in the patients, the S1 amplitude was associated with both language and attention, and the S2 amplitude with both visuospatial/ constructional and language (all p < 0.05), although all of these significances did not pass the Bonferroni corrections. The P50 ratio was not associated with any of the RBANS scores (all p > 0.05).

Our results suggest the P50 suppression deficits in Chinese patients with schizophrenia, which may be associated with cognitive impairments of this illness. Moreover, the amplitude of S1 and the amplitude of S2 may be involved in the different cognitive domain deficits in schizophrenia patients.

This study suggests that the P50 components may possibly be effective biomarkers for cognitive deficits in patients with schizophrenia.