Saccade Characteristics in Patients with Hemispheric Stroke

We examined saccadic velocity and duration under a head-fixed condition in 13 patients with unilateral hemispheric stroke of several months' duration and in 6 healthy control subjects. Eye movements were measured by a standard electro-oculogram technique. The peak saccadic velocity of eye movements away from the brain infarct (contralateral) was lower than that of ocular responses directed towards the infarct (ipsilateral) (p, 0.0005). The mean maximal contralateral saccadic velocity was lower in the pa tient group than in control subjects (p< 0.05) and the mean ipsilateral velocity was only slightly higher than the controls' (p > 0.1) The saccadic duration was longer in pa tients on contralateral movements (p < 0.025). Hemispheric stroke caused impairments of saccadic amplitude-velocity and amplitude-duration relationships (the “main se quence”). It is concluded that in patients who have a unilateral hemispheric stroke, im pairment of hemispheric control of the brain stem saccade generator brings about a de crease in contralateral neural circuit excitation.