Abstract TP31: Resting State Functional MR Connectivity In Acute And Sub-acute Stroke
Objective: Stroke can have important effects on widespread brain regions resulting in network disruption. This study investigates the changes in spontaneous activity in the brain after stroke using resting-state functional connectivity(FC) MRI.
Methods: Acute ischemic stroke patients (N=22, 11 cortical, mean age=60, 10F) were recruited within 7 days of stroke onset(timepoint 1, V1). Eleven of these patients were also scanned at timepoint 2(V2), approximately 3 months later. Age-matched healthy controls (N=17, mean age = 56, 7F) and 7 patients with risk factors for stroke (mean age=67, 1F) were also recruited in the study. Ten minute eyes-closed resting-state fMRI scans were collected along with a high resolution anatomical scan. We examined FC in the language network consisting of ten regions extracted based on functional activations on a phonemic fluency task performed during a separate scan. We also examined the correlation of brain FC with behavioral performance on the task outside the scanner.
Results: We examined correlation between every seed region and every other region in the network(45 seed region-pairs). Compared to age-matched controls, acute strokes showed significantly reduced inter-hemispheric connectivity, specifically between inferior frontal and temporal regions(p<.001 corrected). This difference however was not significant in the sub-acute stage(Figure 1 left panel). Additionally, although both acute and sub-acute patients showed significant differences in performance compared to normals on phonemic fluency(Fig 1 right), there were no significant correlations between brain FC measures and behavior and no differences in the correlation between brain FC and behavior among the groups.
Conclusions: These results suggest that acute strokes show reduced brain connectivity between contralateral regions in the language network; however, this connectivity pattern is restored in the sub-acute stage.
- © 2012 by American Heart Association, Inc.