[Cerebellar infarction restricted to bilateral inferior vermis presenting with floating sensation and then astasia].

A 76-year-old man suddenly experienced floating sensation, transient vertigo, and nausea. Neurological examination was unremarkable except for hypotonia and mild ataxia in the limbs, but orthostatic nausea and vomiting forced him to take a quiet, recumbent position. Magnetic resonance imaging of the brain showed cerebellar infarction restricted to the bilateral inferior vermis. During a course of recovery, he fell down in any directions while standing unattended. He was unable to keep the center of gravity on the feet base in an upright posture. The inferior vermis may participate in maintaining the center of gravity while standing.