BRAIN REGIONS INVOLVED IN THE STRATEGIC PROCESSES OF VERBAL FLUENCY: A MVLSM STUDY IN 337 STROKE PATIENTS

• Published in: Cerebral circulation - cognition and behavior Vol. 6; p. 100057
• Main Authors: Dorchies, Flore, Roussel, Martine, Godefroy, Olivier
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2024; Elsevier
• Subjects: Cognitive science; Neuroscience
• ISSN: 2666-2450; 2666-2450
• DOI: 10.1016/j.cccb.2022.100057

Context: Several studies in verbal fluency have shown the potential of using additional indexes to the number of correct responses in order to determine more precisely the origin of the deficit. On the other hand, studies conducted in functional imaging and pathology report the difficulties in clearly defining the neuroanatomical correlates of these additional indexes.Objective: To examine the patterns of verbal fluency deficits in stroke patients and identify their lesion determinants using the multivariate Voxel-based lesion symptom mapping (mVSLM) method.Method: 337 patients and 851 controls executed the literal and semantic verbal fluency tests analyzed using global and strategic indices (clustering, switching, lexical frequency). Performance profiles were compared between groups and the relationships between verbal fluency, processing speed and naming were studied. mVLSM analyses were performed to identify lesion patterns associated with worse verbal fluency performance.Results: Strategic indexes differed between patients and controls and reflected different processes than those involved in the processing speed and naming tasks (Figures 1–3). In addition, these indexes correlated with partly distinct left hemisphere brain networks. The mVLSM analyses selected the fronto-striatal tract (FST) and uncinate fasciculus (UF) for clustering, anterior thalamic projections (ATP) for switching and lexical frequency, and the superior temporal pole (TP) for lexical frequency only.Conclusion: These results suggest (i) a discriminative ability of strategic indexes reflecting clustering, switching and lexico-phonological or lexico-semantic retrieval processes, (ii) an independence of these indexes to processing speed and naming abilities in cerebrovascular disease, and (iii) a specific involvement of certain brain networks depending on the processes considered.