TARGET PREDICTABILITY INFLUENCES THE DISTRIBUTION OF COORDINATED EYE-HEAD GAZE SACCADES IN PATIENTS WITH HOMONYMOUS HEMIANOPIA

In hemianopic patients target predictability plays a differential role for the distribution of different types of initial saccades. A linear correlation was shown to exist between the adaptive state of reading capability and the probability of a correct initial eye-head gaze sacc ade that hit the target accurately. A constant target frequency of 0.8 Hz was found to be the optimum frequency for hemianopic patients to f ollow square step targets with an eccentricity of +/-20 degrees. Varia bility of the compensatory eye movement velocity gain was lowest at th is frequency. We were able to use this target frequency as a test for a clinical classification of the status of adaptation of hemianopic pa tients in combination with simple reading tests. The repetition of thi s manoeuvre could correct the synkinesis and the balance of the VOR du ring active gaze of hemianopic patients.