SMOOTH-PURSUIT EYE-MOVEMENTS AND EXPRESS SACCADES IN SCHIZOPHRENIC-PATIENTS

Abnormalities of saccades such as disinhibition have been hypothesized as one cause of smooth pursuit eye movement (SPEM) dysfunctions in sc hizophrenia. Thus, we studied saccadic eye movements in schizophrenics with SPEM dysfunction. Subjects were divided into three groups: 10 no rmal control subjects, 10 schizophrenic subjects without SPEM dysfunct ion and 10 schizophrenic subjects with SPEM dysfunction characterized by a cogwheel appearance. Visually guided saccades in gap and overlap paradigms (Saslow, 1967) were examined and saccadic reaction times (SR Ts) were measured in all subjects. Only schizophrenics with SPEM dysfu nctions tended to manifest exessive reflexive saccades, named express saccades (Fischer, 1987), in the gap paradigm. Moreover, most of them were also found to have express saccades in the overlap paradigm, wher eas normal subjects and schizophrenic subjects without SPEM dysfunctio n did not show such phenomena under the same conditions. In particular , most express saccades in the overlap paradigm in schizophrenics with SPEM dysfunction, were found in movements to the right.