Efficacy and Neural Mechanisms of Robotic-Assisted Therapy in Upper Extremity Rehabilitation for Stroke Survivors: A Resting-State fMRI Study

Abstract

Robotic-assisted therapy (RAT) represents a promising adjunctive rehabilitation technology, however, its underlying neuroplastic mechanisms remain incompletely characterized. We aimed to elucidate the neuroplastic reorganization induced by RAT that mediates motor functional improvements in stroke survivors. Thirteen stroke survivors in the RAT group and 13 demographically/clinically matched in the conventional rehabilitation therapy (CRT) group underwent a 4-week rehabilitation intervention. Motor function was assessed using the Fugl-Meyer Assessment upper and lower extremity subscale (FMA-UE, FMA-LE) and modified Barthel Index (MBI) at pre- and post-intervention timepoints. Concurrently, resting-state functional MRI (rs-fMRI) data were acquired for amplitude of low-frequency fluctuation (ALFF) computation and seed-based functional connectivity (FC) analysis. Repeated measures ANOVA showed significant Group $\times $ Time interactions for both FMA-UE and FMA-LE (F(1,24) = 4.913, p<0.05; F(1,24) = 4.778, p<0.05). All motor outcomes displayed strong main effects of Time (all p < 0.001). Post hoc simple effects tests revealed significant within group gains in FMA UE for both RAT and CRT and in FMA LE for RAT only, with no between group differences at any single time point. Neuroimaging showed that increases in ALFF within the ipsilesional precentral gyrus correlated with improvements in both FMA-UE and FMA- LE. Compared with CRT, RAT strengthened interhemispheric functional connectivity between the precentral and postcentral gyri and between the precentral and supramarginal gyri. Together, these findings indicate that RAT promotes motor recovery by up regulating activity in the ipsilesional motor cortex and enhancing cross hemispheric sensorimotor integration, providing the direct evidence for mechanism of post stroke neural restitution. Trial Registration number: ChiCTR2100052592.