Cognitive impairments due to focal cerebellar injuries in adults

Introduction It has been asserted that damage to the cerebellum produces a specific pattern of cognitive deficits, but clinical studies have had ambiguous results. There remains particular uncertainty about the effects of focal cerebellar injuries on cognition in adults. Clinical reports and anatomical connectivity studies have suggested a possible functional convergence of frontal lobes and cerebellum. This investigation was designed to assess whether focal cerebellar injuries in adults would cause impairment on tasks previously demonstrated to be sensitive to prefrontal lesions. Method We investigated this question in 32 adults with either stroke or resection of benign tumours and 36 healthy control subjects. Patients underwent standard and experimental cognitive testing and an assessment of general health and well-being at least 3 months post onset. Results The group with right cerebellar lesions had lower performance on some tests of response control and verbal fluency than the controls and also the patients with left cerebellar lesions. On most tests, including most of the experimental tests sensitive to prefrontal lesions, the patients had no significant difference from the controls. The patient groups reported no health or functional decline. Conclusions These results and the bulk of the clinical literature suggest that damage to some cerebellar sites may have specific cognitive consequences, but the cognitive impairment after focal cerebellar injury in adults is mild or transient. After the acute epoch, demonstration of deficits may require more demanding probes of specific domains of cognition.