ISOLATED HEMIATAXIA AFTER SUPRATENTORIAL BRAIN INFARCTION

Acute isolated hemiataxia is in most cases due to infratentorial (cere bellar) stroke. It has only twice been described in supratentorial str oke-namely, after thalamic infarction and a capsular haemorrhage. Thre e patients with isolated hemiataxia after a supratentorial brain infar ct are described. These patients were seen in a period of five years d uring which 899 patients with a first supratentorial brain infarct wer e registered. Clinically the hemiataxia was of the cerebellar type. In two patients, CT and MRI showed a small, deep (lacunar) infarct restr icted to the posterior limb of the internal capsule, a site not previo usly reported in isolated hemiataxia. The third patient had a small, d eep (lacunar) infarct in the thalamus extending into the adjacent post erior limb of the internal capsule. Isolated hemiataxia after a suprat entorial brain infarct is a very rare clinical stroke syndrome. The ce rebellar type hemiataxia was most likely caused by interruption of the cerebellar pathways at the level of the internal capsule. Our cases c onfirm prior observations that the cerebellar pathways run through the posterior part of the posterior limb of the internal capsule separate ly from the motor and sensory pathways.