Smooth pursuit pattern in schizophrenic patients during cognitive task.

Asymmetries in saccadic pursuit were studied, using EOG, ion 20 schizophrenic patients, as well as in two groups of normal subjects, screened for their patterns of lateral eye movements (LEM). Tracking performance was also examined while subjects were concurrently engaged in performing a cognitive task. Saccadic pursuit among schizophrenic patients was replicated in the present study. No asymmetry was observed in the quality of leftward as compared to rightward tracking. However, solving syllogisms while tracking resulted in further deterioration in tracking performance of the patients, with significantly more saccades and arrests in tracking occurring when following the target to the left as compared to rightward following. Similar asymmetry was observed in one group of controls who are believed to rely more on their left hemisphere on the LEM test, whereas no asymmetry was observed in the performance of the second control group. These results are interpreted as supporting the hypothesis of left hemispheric hyperactivity in schizophrenia. Saccadic pursuit in one subgroup of the normal sample is considered as suggesting that these individuals belong to the high-risk group.