Twenty-one patients with olivopontocerebellar atrophy (OPCA) and 21 normal controls of equivalent age, gender, and educational levels underwent a series of neurobehavioral tests thought to measure frontal lobe and parietal lobe functions as well as information processing speed. The patients with OPCA had higher reaction times and movement times, confirming the results of previous experiments. They had lower scores for some tests thought to be sensitive to dysfunction of the frontal lobe, such as hand sequencing, verbal reasoning, and proverb interpretation. Deficits in copying a simple figure and in immediate visual-spatial memory, thought to be indicative of parietal lobe dysfunction, were also discerned. These results are consistent with the hypothesis that the cerebellum is involved in visual-spatial working memory that requires rapid information processing, and that it modulates parietal lobe- and frontal lobe-mediated functions.