Sensory ataxic hemiparesis in thalamic hemorrhage.

Abstract

Ataxic hemiparesis with cerebellar-like features has been reported following infarction or hemorrhage of the thalamus. We describe five patients with incoordination and corticospinal tract signs in the limbs opposite a dorsolateral thalamic hemorrhage. In four patients the hemorrhage extended superiorly into the lateral ventricle, the adjacent paraventricular region, and the upper and medial parts of the posterior limb of the internal capsule. Instead of cerebellar dysfunction, these patients exhibited directional errors of movement that improved distinctly when performed under visual guidance. We explain the incoordination on the basis of conscious deep sensory loss in the involved limbs. Perception of light touch, painful pinprick, and temperature were preserved in all patients. We use the term "sensory ataxic hemiparesis" to distinguish these patients from those with "classic" ataxic hemiparesis and cerebellar-like features, a distinction that may be important when planning functional rehabilitation.