Saccadic eye movements and regional cerebral blood flow in schizophrenic patients

This study examined saccadic eye movements, using simple stationary targets, in schizophrenic patients. The targets were eight black points or eight arabic-numbered points placed in randomized order on the circumference of a circle. Self-paced eye movements during clockwise tracking of these points, by 23 patients and 23 controls, were recorded using an infrared eye-mark recorder. Then the relationship between the saccades and clinical symptoms was investigated. Finally, the relationship between the performance of the saccades and resting regional cerebral blood flow (rCBF) was examined using single photon emission computed tomography with 99mTc-hexamethyl propyleneamine oxime (HMPAO). The results indicate that patients track with significantly fewer correct scores and more deviant scores than controls, in agreement with our previous study. There were two groups of patients: an ordinary group who obtained a full-target-hitting score at a 200-ms setting and a fast group who obtained the full score at 100 ms but not at 200 ms. Some patients displayed significantly more hypermetria than controls. Significant correlations were found between hallucination and delusion symptoms and correct score. With respect to relative rCBF, fast-group patients showed significantly decreased rCBF in the left limbic and inferior parietal areas as compared with ordinary group patients. These findings suggest that some schizophrenic patients view the stationary targets too fast and this may be related to dysfunction in the limbic-parietal association area in the left hemisphere.