Stockbridge, Melissa D.

Background: Stroke is a leading cause of mortality and long-term disability, and aphasia is among its most common and debilitating sequelae. Diffusion tensor imaging (DTI) and advanced diffusion imaging techniques enable the assessment of white matter integrity and provide clinically relevant measures in post-stroke aphasia. Methods: We conducted a comprehensive review of studies applying DTI or advanced diffusion imaging to investigate structural connectivity in adults with post-stroke aphasia (PSA). PubMed, CENTRAL, Ovid MEDLINE, and Embase were searched, and eligible studies were synthesized according to their diagnostic, prognostic, or therapeutic focus. Results: Ninety-five studies were included. Of these, 59 were classified as diagnostic, 17 as prognostic, and 19 as therapeutic. Most studies employed conventional DTI (n = 77), while a growing body of research utilized advanced diffusion models, including CSD, DSI, and DKI (n = 18). Conclusions: This comprehensive synthesis demonstrates the evolution of diffusion imaging in PSA research. While conventional DTI has provided foundational insights, advanced diffusion methods offer superior characterization of complex fiber architecture and improved clinical–anatomical correlation. Diffusion-derived markers of dorsal and ventral language pathways were consistently associated with language performance, while connectome-level analyses highlighted the importance of preserved global network architecture for recovery. Continued efforts are needed to translate diffusion imaging findings into clinical applicable biomarkers to guide personalized aphasia rehabilitation, with greater use of advanced methods.

Background and Objectives: Stroke is a leading cause of disability worldwide. Recent studies have suggested the feasibility and potential utility of remotely supervised transcranial direct current stimulation (RS-tDCS) to improve different types of impairments in various neurological conditions. This scoping review provides a critical appraisal of RS-tDCS as an adjunct therapy to enhance recovery after stroke. Materials and Methods: A comprehensive literature review was systematically conducted using PubMed through Nested Knowledge software. A supplementary search was conducted in Google Scholar. Two independent authors screened and identified related studies investigating RS-tDCS in patients with stroke from inception to February 2025. Results: Studies showed that RS-tDCS was safe, with only mild side effects. Additionally, it was feasible, with high adherence rates likely due to ease of use. Regarding efficacy, RS-tDCS preliminarily yielded improvements in upper- and lower-limb motor functions and increased language and cognitive performance. However, the studies were underpowered and heterogeneous, limiting generalization of findings. Conclusions: RS-tDCS is safe and feasible, affording beneficial effects in the motor, language, and cognitive functions of patients with post-stroke impairments. RS-tDCS has the potential to improve access and reduce disparities for post-stroke experimental treatments. However, adequately powered randomized trials are needed to further investigate the efficacy.

Abstract Studies have shown that the integrity of white matter tracts connecting different regions in the left cerebral hemisphere is important for aphasia recovery after stroke. However, the impact of the underlying structural connection between the cortex and the cerebellum in post-stroke aphasia is poorly understood. We studied the microstructural integrity of the cerebellum and the corticocerebellar connections and their role in picture naming. Fifty-six patients with left cerebral infarcts (sparing the cerebellum) underwent diffusion tensor imaging (DTI) and Boston Naming Test. We compared the fractional anisotropy (FA) and mean diffusivity (MD) values of the right and the left cerebellum (lobular gray and white matter structures) and cerebellocortical connections. Recursive feature elimination and Spearman correlation analyses were performed to evaluate the relationship between naming performance and the corticocerebellar connections. We found that the right, relative to left, cerebellar structures and their connections with the left cerebrum showed lower FA and higher MD values, both reflecting lower microstructural integrity. This trend was not observed in the healthy controls. Higher MD values of the right major cerebellar outflow tract were associated with poorer picture naming performance. Our study provides the first DTI data demonstrating the critical importance of ascending and descending corticocerebellar connections for naming outcomes after stroke.