Affiliations: [a]
Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| [b]
Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| [c]
Department of Neurology, University of Cincinnati Academic Health Center, Cincinnati, OH, USA
| [d]
Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| [e]
Department of Emergency Medicine, University of Cincinnati Academic Health Center, Cincinnati, OH, USA
| [f]
currently at Department of Biostatistics, Vanderbilt University, Department of Biostatistics, Nashville, TN, USA
Correspondence:
[*]
Corresponding author: Rodolphe Nenert, Ph.D., Department of Neurology, 312 Civitan International Research Center, 1719 6th Avenue South, Birmingham, AL 35294-0021, USA. Tel.: +1 205 975 3885;[email protected].
Abstract: Background:Recovery from stroke-induced aphasia is typically protracted and involves complex functional reorganization. The relative contributions of the lesioned and non-lesioned hemispheres to this process have been examined in several cross-sectional studies but longitudinal studies involving several time-points and large numbers of subjects are scarce. Objective:The aim of this study was to address the gaps in the literature by longitudinally studying the evolution of post-stroke lateralization and localization of language-related fMRI activation in the first year after single left hemispheric ischemic stroke. Method:Seventeen patients with stroke-induced aphasia were enrolled to undergo detailed behavioral testing and fMRI at 2, 6, 12, 26, and 52 weeks post-stroke. Matched for age, handedness and sex participants were also enrolled to visualize canonical language regions. Results:Behavioral results showed improvements over time for all but one of the behavioral scores (Semantic Fluency Test). FMRI results showed that the left temporal area participates in compensation for language deficits in the first year after stroke, that there is a correlation between behavioral improvement and the left cerebellar activation over time, and that there is a shift towards stronger frontal left-lateralization of the fMRI activation over the first year post-stroke. Temporary compensation observed in the initial phases of post-stroke recovery that involves the non-lesioned hemisphere may not be as important as previously postulated, since in this study the recovery was driven by activations in the left fronto-temporal regions. Conclusion:Language recovery after left hemispheric ischemic stroke is likely driven by the previously involved in language and attention left hemispheric networks.
