Affiliations: Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA | Department of Neurology, University of Cincinnati Academic Health Center, Cincinnati, OH, USA | Department of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA | Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA | Department of Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
Note: [] Corresponding author: Jerzy P. Szaflarski, MD, PhD, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 312, Birmingham, AL, USA. Tel.: +1 205 934 3866; Fax: +1 205 975 6255; E-mails: szaflaj@uab.edu; allendjb@uab.edu (J. Allendorfer); christi.banks@uc.edu (C. Banks); jennifer.vannest@cchmc.org (J. Vannest); scott.holland@cchmc.org (S. Holland).
Abstract: Purpose: Several adult studies have documented the importance of the peri-stroke areas to aphasia recovery. But, studies examining the differences in patterns of cortical participation in language comprehension in patients who have (LMCA-R) or have not recovered (LMCA-NR) from left middle cerebral artery infarction have not been performed up to date. Methods: In this study, we compare cortical correlates of language comprehension using fMRI and semantic decision/tone decision task in 9 LMCA-R and 18 LMCA-NR patients matched at the time of stroke for age and handedness. We examine the cortical correlates of language performance by correlating intra- and extra-scanner measures of linguistic performance with fMRI activation and stroke volumes. Results: Our analyses show that LMCA-R at least 1 year after stroke show a return to typical fMRI language activation patterns and that there is a compensatory reorganization of language function in LMCA-NR patients with shifts to the right hemispheric brain regions. Further, with increasing strength of the left-hemispheric fMRI signal shift there are associated improvements in performance as tested with standardized linguistic measures. A negative correlation between the size of the stroke and performance on some of the linguistic tests is also observed. Conclusions: This right-hemispheric shift as a mechanism of post-stroke recovery in adults appears to be an ineffective mode of language function recovery with increasing right-hemispheric shift associated with lower language performance. Thus, normalization of the post-stroke language activation patterns is needed for better language performance while shifts of the activation patterns to the non-dominant (right) hemisphere and/or large stroke size are associated with decreased linguistic abilities after stroke.
