Exploratory eye movements and neuropsychological tests in schizophrenic patients

Exploratory eye movements in schizophrenic and nonschizophrenic subjects were examined with an eye mark recorder while the subjects viewed geometric figures. Elementary components of eye movements and the responsive search score (RSS), a function of the number of sections on which the subjects fixated, were measured by means of an eye movement analyzer and slow motion replay. The schizophrenic group and the depressed patient group had fewer eye fixations than the normal control group and the obsessive-compulsive disorder group. The schizophrenic group had a lower RSS average than patients with depression, patients with obsessive-compulsive disorders, or subjects in the normal control group. These results in conjunction with those of our previous studies suggest that a low RSS is specific to schizophrenia. We examined the relationship between these eye movements and neuropsychological tests and also investigated the relation between the eye movements and clinical symptoms by means of the Brief Psychiatric Rating Scale, Schedule for Affective Disorders and Schizophrenia, and the Scale for the Assessment of Negative Symptoms. The RSS correlated positively with the performance IQ and Wechsler's Maze test, but not with the Wisconsin Card Sorting Test or the verbal IQ result. The RSS also correlated negatively with negative symptoms. These results suggest that the RSS has two characteristic features: it is strongly associated with the interpersonal response and it may be connected with visuospatial and visuomotor functions including attention.