Event-related potentials in schizophrenic patients: Clinical and neurophysiological correlates

In the present study event-related potentials, reaction time, number of errors and number of omissions were recorded in a group of DSM III diagnosed schizophrenic patients and in a closely matched control group. A target detection paradigm was used in which the verbal stimuli (consonant pairs) were presented in a central and in a lateral condition. Independent Principal Component Analysis and Varimax Rotation were performed for each condition. Separate ANOVAs were performed on factor scores computed for each rotated principal component. In the central condition P440 activity was reduced in patients as compared with normal controls, and this reduction was associated with a pronounced negative symptomatology. No pattern of lateral asymmetry was found in either group. The lateral condition showed differences in lateralization patterns between patients and controls for both event-related potentials and behavioral indexes. These differences suggest a delayed processing and a left hemisphere dysfunction in schizophrenics.