Event-related dynamics of brain oscillations during perception of verbal information in patients with paranoid schizophrenia

We studied the evoked changes in brain rhythmic activity during reading semantic (words) and meaningless verbal information (pseudowords) in patients with paranoid schizophrenia (n= 40) and in control group of healthy subjects (n= 64). Patients with paranoid schizophrenia showed the decrease in the event-related synchronization (ERS) of alpha and theta rhythms compared to controls when reading semantic verbal information. Reduced event-related synchronization of the alpha rhythm in time window 105 - 145 ms may be associated with the severity of hallucinations (P3 scale) by PANSS. In contrast to the control group, the patients had no differences in the gamma range when reading words and pseudowords. This fact may indicate that patients with paranoid schizophrenia assign significance to those stimuli that are not normally considered as significant (pseudowords).