Vertical one-and-a-half syndrome Clinical, oculography and radiologic findings

Abstract

Supranuclear downgaze paralysis with monocular elevation palsy, better known as vertical 'one-and-a-halF syndrome, results from lesions affecting the mesodiencephalic region. In this clinical observation, downgaze paralysis was characterized by: impairment of all downward rapid eye movements (including vestibulo-ocular movements) and foveal smooth pursuit (nondis-sociated downgaze paralysis). Electrophysiologic and magnetic resonance imaging documented analysis of this complex oculomotor syndrome, referred to bilateral infarction at the thalamomesen-cephalic junction, in the bottom of the third ventricle in the region of the upper medial part of the red nucleus. From these findings it was postulated that the lesions may have affected the efferent tracts of the rostral interstitial nucleus of the medial longitudinal fasciculus bilaterally and the pre-motor fibres to the contralateral superior rectus subnucleus and ipsilateral inferior oblique sub-nucleus, either before or after decussation in the posterior commissure.