The effects of focal anterior and posterior brain lesions on verbal fluency
Journal of the International Neuropsychological Society
Seventy-four patients with focal brain lesions were compared to a neurologicallynormal control group on tasks of letter-based and category-based listgeneration. When patients were divided only by right frontal, left frontal, ornonfrontal lesion sites, the pattern of fluency impairments confirmed priorclaims. When more precise lesion sites within the frontal lobes were comparedbetween groups classified based on their fluency performance, much more specificbrain-behavior relations were uncovered. Damage to the right dorsolateralcortical or connecting striatal regions, the right posterior area, or the medialinferior frontal lobe of either hemisphere did not significantly affectletter-based fluency performance. Superior medial frontal damage, right or left,resulted in moderate impairment. Patients with left dorsolateral and/or striatallesions were most impaired. Left parietal damage led to performance relativelyequivalent to the superior medial and left dorsolateral groups. The same lesionsites produced impairments in category based fluency, but so did lesions of right dorsolateral and inferior medial regions. Task analysis and correlationswith other measures revealed that different cognitive processes related todifferent brain regions underlie performance on verbal fluency tests.Publication Types: Clinical Trial
Stuss D.T., Alexander M.P., Hamer L., Palumbo C., Dempster R., Binns M., Levine B. & Izukawa D.