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62 EEGs of 5 min recordings, over C4-P4, P4-02, C3-P3, P3-01, have been recorded from 31 schizophrenic patients and 31 controls, matched for age (27 years) and sex (males). Patients were clinically classified into 3 sub-groups: paranoid-type P(7), residual type R(10) and others O(14). Controls were statistically classified into 2 sub-groups as high alpha subjects HA(15) or low alpha subjects LA(16). Following computer Fourier statistical analysis, evolutive power spectra, averaged power spectra and spectral variances were obtained for each EEG recording. Date reduction provided for each EEG: Mean frequencies, mean amplitudes in microvolts and percentage asymmetries, resonance, spectral parameters; theta/alpha, with their variabilities. Power spectra were averaged between patients or between subjects for each sub-group. The alpha peak and the mean RMS amplitude was higher over P3-01 than over P4-02 for the residual-type of schizophrenic patients, when compared to his matched control sub-group of high-alpha subjects which presented almost symmetrical occipital alpha peaks and RMS amplitudes. However, the most important changes appear to be intra-hemispheric. The alpha peaks and RMS amplitudes were almost equal between C3-P3 and P3-O1 for the paranoid type of schizophrenic patients in contrast to other sub-groups and especially both control sub-groups. This seems to imply left hemispheric changes in terms of EEG spectral alpha intensities, when tracings of schizophrenics were compared with recordings of volunteers.

Spectral analysis of tracings from four leads; C3-P3, P3-O1, C4-P4, and P4-O2, were used to compare the results of fiftyseven electroencephalograms from 10 schizophrenics, and 14 normal subjects used as controls. The results show that the mean frequencies of the alpha waves are identical in schizophrenics and controls. Patients with hebephrenia show the lowest variations in alpha wave frequency but with the highest voltage, whereas paranoid schizophrenics have tracings with the lowest amplitude and the greatest variation in frequency. There is also better left intrahemispheric correlation of relative alpha intensities in those patients with the lowest variation in right alpha intensity in relation to controls. The preliminary results suggest that there is a reduction in functional asymmetry of the hemispheres in the electroencephalograms from schizophrenics, when looking at the alpha activity.