Smooth pursuit eye movement and directional motion contrast sensitivity in schizophrenia

Abstract Although the presence of a visual processing and eye movement disorder in schizophrenia have been widely recognized their relationship with the symptoms of schizophrenia is less well understood. In two experiments the relationship between directional motion sensitivity and smooth pursuit eye movement was investigated in normal observers and in subgroups with predominantly positive- and negative-symptoms in schizophrenia. The first experiment measured linear smooth pursuit eye movement at six target velocities from 5.0 to 30.0 deg/s, and the second experiment measured directional motion contrast sensitivity at three spatial (1.0, 4.0 and 8.0 c/deg) and five temporal (0.75, 3.0, 6.0, 12.0, 18.0 Hz) frequencies in the same groups of observers. No significant differences were found between the control and positive-symptom group in directional motion contrast sensitivity and smooth pursuit eye movement. In comparison, a significant reduction in directional motion contrast sensitivity and in smooth pursuit eye movement was found in the negative-symptom group. The relationship between visual motion processing and pursuit eye movement in the negative-symptom group was explained by lowered directional motion processing that fails to fully engage the pursuit eye movement system and results in lowered smooth pursuit eye-velocity gain.