Associations between stroke lesion location and verbal fluency tests in a sub-acute stroke population

Background: In stroke hospitalizations, verbal fluency tests are used to evaluate executive abilities in order to assess the integrity of functioning and language. Prior studies show that clustering and switching during verbal fluency tasks are related to functioning of specific brain regions, such that they are thought to be more sensitive in detecting impairments in frontal regions compared to other brain regions. Objective: Investigate the hypothesis that the stroke lesion location predicts both quantitative and qualitative (clustering and switching) aspects of fluency. Patients with frontal lesions will perform poorly on switching and phonemic tasks, while the patients with temporal lesions will perform poorly on clustering semantic tasks. Method: Stroke inpatients (N=99) completed verbal fluency measures and structural brain scans within 72 hours of admission. Healthy controls (N=39) were recruited and administered verbal fluency measures. Fluency performance was evaluated by valid qualitative and quantitative analysis. Results: Lesion location did not predict qualitative aspects of fluency and provided no support that frontal region lesions result in impairments in executive function. Hemispheric lesion location was not significant. Stroke patients preformed more poorly on fluency measures compared to controls. Conclusion: Verbal fluency performance is affected by vascular brain damage resulting from stroke, but lesion location does not differentially affect qualitative or quantitative aspects of verbal fluency performance. Correspondence to: GM Babulal, Department of Neurology, Washington University School of Medicine, Campus Box 8111 4488 Forest Park, St. Louis, MO 63110, USA; Tel: (952) 334-8536; E-mail: [email protected]