DIMENSIONAL COMPLEXITY OF EEG BRAIN MECHANISMS IN UNTREATED SCHIZOPHRENIA

The dimensional complexity of left temporal-parietal and parietal-occi pital electroencephalographic (EEG) recordings was assessed by computi ng the correlation dimension during 20 sec in six recording conditions from 15 first-episode acute schizophrenics before medication, 12 othe r medication-free individuals clinically and socially remitted after a first schizophrenic episode, 17 medication-free neurotics and 17 cont rols. The correlation dimension of the temporal-parietal EEG differed between groups [analysis of variance (ANOVA)] (p < 0.001); it was sign ificantly higher in first-episode schizophrenics than in controls (p < 0.004), whereas neurotics (different from schizophrenics at p < 0.002 ) and remitted schizophrenics showed intermediate values. There was no overall significant difference between groups in the parietal-occipit al EEG. Differences of the correlation dimension of the temporal-parie tal versus the parietal-occipital EEG were significant between groups (ANOVA p < 0.05); first-episode schizophrenics differed from controls (p < 0.002) and remitted patients (p < 0.08). Increased dimensional co mplexity of schizophrenic EEG was found in one of two examined brain r egions. The higher dimensional complexity of functional brain mechanis ms in schizophrenics versus normals is reminiscent of the loosened org anization of thought, and of suggestions of certain superior abilities in the patients.