capsular infarct

SUMMARY Two patients presenting with hemiataxia and hemiparesis on the same side are described. Both had cr scan evidence of an infarct located in the posterior limb of the con-tralateral internal capsule. The association of cerebellar ataxia and pyramidal signs involving the limbs of the same side was first described by Fisher and Cole ' in 1965, who tenta-tively located the lesion in the posterior limb of the internal capsule. Subsequently ataxic hemiparesis has been reported in six patients with lesion in the basis pontis contralateral to the involved limb,25 in a patient with a ventrolateral midbrain lesion6 and in three patients showing CT scan evidence of an infarct of the posterior limb of the internal cap-sule.7-9 We report two more cases of ataxia and homolateral crural paresis. In both patients a lesion located in the posterior limb of the internal capsule was identified on the CT scan. Case I A 45-year-old man was admitted to the wards after the sudden onset of a right hemiparesis. On neurological examination he was alert and oriented. Speech and cranial nerves were normal. There was slight right-sided weakness of the peroneal muscles with minimal weakness of the extensor muscles of the right arm. Tendon reflexes on the right were slightly brisker than those on the left and the right plantar response was extensor. On standing with the feet together the patient fell to the right. There was a severe dysmetria on both finger-to-nose and heel-to-knee tests. Rapid alternating movements were slow and clumsy on the right side. Sensory functions and visual fields were normal. Weakness and ataxia increased in a step-wise fash-ion in the next two days. Weakness was greater in the proximal muscles of the upper limb and in the distal mus-cles of the lower limb. At the end of the fourth week of illness the right arm had completely recovered its strength