Abnormalities of cerebral lateralization in schizophrenia patients

Initial lateral eye movements (LEMs) have been shown to be associated with activation of the contralateral frontal lobes. Using LEM as a criterion measure of activation, schizophrenics were compared to normals with respect to the processing of four types of stimuli: verbal nonemotional (VNE), verbal emotional (VE), spatial nonemotional (SNE), and spatial emotional (SE). Our results indicate that schizophrenics initiate thought in their left hemisphere significantly more often than controls when one compares all test conditions and on VNE, VE, and SE material. Neither medication nor level of education had an appreciable effect on LEM in either group. However, sex was a significant variable; women irrespective of diagnosis consistently used the left hemisphere more often than men. The inappropriate initiation of thought on SE material as well as the overall increase in left hemisphere activity suggest left hemisphere disorder. This is consistent with other findings that suggest a left hemisphere locus of disturbance in schizophrenia.