A 62-yr-old woman with a history of hypertension and diabetes presented to an outside hospital with right side weakness. Computed tomography showed a hemorrhage in the left basal ganglia and lentiform nucleus. On admission to acute inpatient rehabilitation a week later, strength was 5/5 on the left side and 3/5 on the right. On the finger-to-nose test on the right, she lost a smooth trajectory approximately 75% of the way through the reaching process and then had small amplitude vertical oscillations before reaching the target. She ambulated 100′ using a rolling walker with minimum assistance to recover occasional loss of balance especially during turns and demonstrated inconsistent right foot placement and clearance. When discharged 12 days later, strength was 4/5 on the right, dysmetria was improved but retaining the same characteristics (Video 1), and she ambulated 300′ and negotiated 2+ turns with a rolling walker.
Ataxia and dysmetria associated with midbrain lesions have been recognized for over a century. Seven of 13 patients with a stroke in the lentiform nucleus were found to have ataxia.1 We have not seen the dysmetria secondary to a stroke in the lentiform nucleus characterized or illustrated. The rehabilitation courses of patients with noncerebellar ataxia-dysmetria syndromes have recently been discussed, and it has also been appreciated that the dysmetria in these syndromes is different than that caused by a cerebellar lesion and indeed distinct to each lesion site: in patients with a thalamic lesion,2 dysmetria does not start until the last ~25% of end range reaching and there is no hemiparesis. Pontine lesions usually present with some degree of hemiparesis, which usually improves quickly, and dysmetria3 starting the first 30% of the reaching process. Lesions in the corona radiata cause hemiparesis and dysmetria3 that starts about halfway into the reaching process. We suggest that a stroke in the lentiform nucleus can cause a contralateral ataxia-dysmetria syndrome, presumably due to a lesion of pontocerebellar fibers, with the dysmetria being most similar in character, but with a smaller amplitude of oscillations, to that seen in patients with thalamic strokes (Video 1).2
This study conforms to all CARE guidelines and reports the required information accordingly (see Supplemental CARE Checklist file, Supplemental Digital Content 1, http://links.lww.com/PHM/A820). The patient gave written consent for use of the video.
1. Russmann H, Vingerhoets F, Ghika J, et al: Acute infarction limited to the lenticular nucleus: clinical, etiologic, and topographic features. Arch Neurol
2. Menard R, Shah A, Metzger C, et al: Thalamic dysmetria. PM R
3. Mohar M, Hartman K, Long B, et al: Rehabilitation course and specification of dysmetria of a patient with ataxia, dysmetria, and hemiparesis after a stroke in the corona radiata: a case presentation. PM R