The cerebellum and cognitive functions in humans.

Recent neuropsychological studies have given rise to the hypothesis that the cerebellum is involved in nonmotor cognitive functions. The interpretation of these findings is, however, restricted by methodological problems, such as heterogenous patient samples. The present study compared patients with pathology confined to the cerebellum and patients with combined cerebellar and brainstem lesions to matched normal controls on a range of memory and learning tasks. Two procedural learning tasks were also conducted, involving perceptual (mirror reading) and conceptual skill acquisition (the Tower of Hanoi task). Patients with damage to both cerebellum and brainstem, but not patients with cerebellar pathology alone, showed impairments on memory and visuoconstructive tasks and evidence of frontal lobe dysfunction. Cerebellar damage had no effect on skill acquisition. These results do not support the hypothesis of cerebellar involvement in procedural learning per se.