Cognitive impairment in young adults with infratentorial infarcts

OBJECTIVE: To describe cognitive functions and functional outcome in young patients with isolated infratentorial infarcts. BACKGROUND: Contemporary knowledge implies a cerebellar contribution to cognitive behavior. Neuropsychological examination of patients with selective cerebellar lesions provides an opportunity to document the existence and nature of clinically relevant cognitive manifestations from lesions of the cerebellum. METHODS: Prospective case series. The patients were assessed acutely and at 4 and 12 months after onset. Twenty-four patients from a consecutive series of 105 patients aged 18 to 44 years with cerebral infarction had a brain stem or cerebellar infarction. Fourteen age-matched controls were used for neuropsychological comparisons. Evaluation included MRI, angiography, and transesophageal echocardiography. Disability and neurologic dysfunction were assessed by the modified Rankin scale, NIH stroke scale, and maximal working capacity. A comprehensive neuropsychological battery was performed at baseline in 20 of the 24 patients. RESULTS: Eighteen patients had a cerebellar infarct. Two patients had lateral medullary infarcts, and two isolated pontine infarcts. Twenty-two patients had a favorable outcome according to the modified Rankin scale (grade 0-2) and the NIH scale. In contrast, 12 patients were granted full or partial sick leave at the 4 months follow-up, and 10 patients at 12 months. Patients generally performed worse than controls in various aspects of cognitive function, especially in tasks concerning working memory, the temporary storage of complex information, and cognitive flexibility. Measures of verbal IQ (r = -0.74) and performance IQ (r = -0.78) were related to the size of the infarct. The block design task performance in the early poststroke period predicted maximal working capacity at 12 months. CONCLUSIONS: Cerebellar damage impairs central aspects of attention and visuospatial skills. In contrast, intelligence and episodic memory remain unchanged. When the lesion involves large portions of the cerebellar hemispheres, changes concerning broad areas of intelligence may occur. The prognosis is favorable for neurologic dysfunction, but cognitive deficits may prevent return to work.