Topographical EEG differences between schizophrenic patients and controls during neuropsychological functional activation.

Ten DSM III schizophrenic patients belonging to an Active syndrome were compared with 10 age- and sex-matched normal controls on neuropsychological tests with concurrent monitoring of topographical EEG using a brain imager with a 28-electrode array. In line with predictions, abnormalities in patients were found in tests involving right hemispheric functions. Deficits were found in recognition memory for faces as distinct from a verbal recognition memory task. Right temporo-parietal involvement in the faces task was confirmed by an absence of beta II amplitude reduction in patients compared with controls in the right temporo-parietal region. A similar anomaly occurred in patients in a left- but not right-hand finger-thumb apposition test in left anterior and right posterior regions, and also in a passive visual fixation task where it was located bilaterally in the occipito-parietal region. Functional activation with neuropsychological tests holds promise as one approach to the validation of topographical mapping of brain electrical activity.