Eye tracking disturbances in schizophrenia.

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.