Neural reorganization after aphasia therapy: a scoping review of resting-state functional connectivity changes

BackgroundAphasia, a common consequence of stroke, significantly impairs language function, necessitating rehabilitation strategies that leverage neuroplasticity for effective recovery. Insights into the neural underpinnings of language recovery are vital for optimizing therapeutic approaches.ObjectiveThis scoping review synthesizes empirical findings on the modulation of resting-state functional connectivity (rsFC) following speech and language therapy (SLT) in individuals with post-stroke aphasia (PWA), in order to better understand and add to attempts to map the neural trajectory of recovery.MethodsA comprehensive search was conducted in the PubMed and Web of Science databases to identify relevant studies. Covidence Systematic Review Software, 2022 was employed to manage the initial and full-text screening process. Following PRISMA guidelines, we systematically reviewed studies examining rsFC changes after SLT in PWA. We included studies that utilized rsfMRI in addition to behavioral assessments to ascertain the neural correlates of therapeutic intervention.ResultsEleven studies were reviewed, highlighting an overall increase in intra-hemispheric connectivity, particularly within the left hemisphere, and a complex pattern of inter-hemispheric connectivity changes post-treatment. Increased connectivity within language-specific and domain-general regions suggests a dynamic neural reorganization towards a more efficient network configuration. Graph theory analysis illuminates the balance between network segregation and integration, with implications for the "small-world" characteristics of optimal brain function during recovery.ConclusionOur review indicates that SLT fosters significant neuroplastic changes in rsFC associated with language recovery in PWA. These changes reflect the adaptive reorganization of both language-specific and domain-general networks. However, the variability in treatment modalities, analytic methods, and the need for standardized approaches in rsfMRI research limit generalizability. Future research should focus on the refinement and systemization of methods and should aim to elucidate the roles of intra- and inter-hemispheric connectivity in aphasia recovery and refine rsfMRI's potential as a biomarker for treatment outcomes.