Eye tracking disturbances in schizophrenia.

ABSTRACT

PURPOSE: To study the frequency of different types of eye tracking disturbances in schizophrenia. MATERIALS AND METHODS: Smooth pursuit eye movements were studied by electro-oculography (EOG) in 22 schizophrenic patients (ICD-10 criteria) and 15 age and sex-matched controls. The studied parameters included average pursuit gain, number of saccades, the frequency of different types of saccades (catch-up, back-up, anticipatory saccades), and disturbances during fixation. The results were analysed statistically. RESULTS: The average pursuit gain was significantly affected in patients for target velocity of 30 degrees/sec (p = 0.007). The catch-up and back-up saccades were more common in cases than controls but the difference was not significant (p = 0.39 and 0.36 respectively). The anticipatory saccades were significantly more frequent in cases than controls (p < 0.0001) for both 15 degrees/sec and 30 degrees/sec target velocities. This was also correlated with the duration of illness. CONCLUSION: Anticipatory saccades are significantly more frequent during eye tracking in schizophrenia and appear to be an objective marker for the disease.