Oculomotor disorders in cortical lesions in man: the role of unilateral neglect.

The saccades of 22 patients with lesions of the left (6) and right (16) hemisphere were analysed. Seven patients with a right hemispheric lesion presented a left unilateral neglect (UN) syndrome. In the first test session the saccades were performed in response to a predicted sequence of targets; in the second session the luminous stimuli were unpredicted and randomized. In patients with UN we observed the absence of saccadic response to 25% of the targets a lengthening of the reaction time and a staircase pattern in the left hemifield. In the predicted stimulus sequence the oculomotor performance was not significantly better. Hemianopia, a defect of arousal and an altered visuospatial orientation are the most important elements that account for the alterations of oculomotor strategy in the UN syndrome.