Relative advance of eye movement to the target in the rightward tracking in schizophrenics.

Time relationship between the horizontal smooth pursuit eye movement (SPEM) and tracking target in the leftward or rightward tracking was investigated in 28 normal and 25 chronic schizophrenic subjects. Normal subjects were more liable to show a relative advance of SPEM in relation to the target in the leftward pursuit than in the rightward pursuit. These findings suggest that the spatial task such as SPEM depends more on the right hemispheric function in normal subjects. On the other hand, many of schizophrenic subjects showed a relative advance of SPEM to the target in the rightward pursuit. These findings suggest the dominance of the left hemispheric function in eye tracking tasks in schizophrenic subjects. The finding in the present study would support the hypothesis of the left hemispheric overactivation in the schizophrenic patients.