Wallenberg's syndrome: lateropulsion, cyclorotation, and subjective visual vertical in thirty-six patients.

We measured the subjective visual vertical, cyclorotation of the eyes, and head and body lateropulsion in 36 patients with Wallenberg's syndrome. All patients exhibited significant tilts of the internal representation of the gravity vector, as indicated by deviation of subjective visual vertical ipsiversive to the lesion. Most patients (82%) had ipsiversive cyclorotation of one or both eyes, especially excyclotropia of the eye ipsilateral to the brainstem lesion. Twelve of 36 patients (33%), those with the most severe body lateropulsion, had a complete ocular tilt reaction consisting of head tilt, skew deviation, and cyclorotation in the roll plane. We hypothesize that deviation of subjective visual vertical, lateropulsion of the body, and cyclorotation of the eyes are the perceptual, the ocular motor, and the postural consequences of a common lesion of central vestibular pathways that subserve the vestibuloocular reflex in the roll plane. Lateropulsion in patients with Wallenberg's syndrome is interpreted as a postural consequence of an abnormal tilt of the internal representation of orientation in space.