Ataxic hemiparesis. A pathologic study.

Three stroke patients showed weakness and pyramidal signs on one side combined with a cerebellar-like ataxia on the same side. Pathologic study in each case showed an old infarct cavity in the basis pontis at the level of the junction of the upper one third and lower two thirds on the side opposite the neurologic deficit. The basilar artery was patent and the infarcts were probably the result of occlusion of penetrating arteries. This study demonstrates that a lesion of the basis pontis may be associated with a contralateral ataxia that is cerebellar in character. The designation ataxic hemiparesis is suggested for the syndrome.