Abstract
The cerebellum has emerged as a potential target for transcranial direct current stimulation (tDCS) in post-stroke aphasia (PSA) due to its role in language processing and relative preservation compared to supratentorial lesions. Recent evidence also highlights the cerebellum's involvement in affective and social processes, suggesting potential broader effects of cerebellar modulation. This study investigated the efficacy of anodal tDCS over the right cerebellum paired with speech and language therapy in enhancing language functions and quality of life in individuals with PSA. Twenty-two participants with chronic PSA received cerebellar tDCS, while historical sham control data from 25 participants were obtained. Language outcomes were assessed using the Western Aphasia Battery-Revised (WAB-R), and secondary outcomes included patient-reported measures of communication effectiveness and quality of life. Mixed-design analyses of variance were conducted to examine treatment effects. No significant Group x Time interaction was found for WAB-R scores, indicating that tDCS did not provide additional language benefits over speech therapy. However, a significant Group x Time interaction was observed for the Stroke and Aphasia Quality of Life Scale-39 scores, driven by improvements in the Psychosocial, Physical, and Energy subdomains in the tDCS group. Cerebellar tDCS did not significantly improve language outcomes in PSA individuals but enhanced specific aspects of quality of life. These findings highlight the cerebellum's multifaceted role in cognitive, affective, and sensorimotor processes. Future research should focus on conducting well-powered, randomized, double-blind, and concurrent trials to validate these findings and explore optimal stimulation parameters in PSA rehabilitation.Trial registration: The trial is registered at ClinicalTrials.gov with the registration number NCT03699930. The date of registration is 10/05/2018.