Lateropulsion in Wallenberg's syndrome and contrapulsion in the proximal type of the superior cerebellar artery syndrome

Abstract

Two patients with leftward bias of the eyes during vertical saccades were studied by electro-oculography. One patient with left Wallenberg's syndrome showed the characteristic eye-movement disorders with leftward overshooting and rightward ‘staircase’ undershooting during horizontal saccades. The other patient, with the right proximal type of superior cerebellar artery syndrome, showed overshooting dysmetria sequentially diminishing in amplitude to the contralateral side of the cerebellar lesion and ipsilateral hypometric dysmetria. Because these two syndromes are neurologically similar, a careful study of the eye movements may provide a useful clue for the clinical diagnosis. The authors' study showed that these two syndromes have opposite directions of lateropulsion during vertical saccades in relation with the neurological signs, i.e, lateropulsion and contrapulsion respectively, and also a predominance of cerebellar oculomotor disturbances during horizontal saccades in the proximal occlusion of the superior cerebellar artery.

Key Words:

• lateropulsion
• contrapulsion
• Wallenberg's syndrome
• superior cerebellar artery syndrome
• ocular dysmetria
• magnetic resonance imaging