Grip training improves handgrip strength, cognition, and brain white matter in minor acute ischemic stroke patients

Objective: A large proportion of stroke patients experience cognitive impairment. Previous studies found that handgrip training can improve cognitive dysfunction after stroke through an unknown mechanism. In this study, we aimed to examine the influence of handgrip training on the cognition of patients with acute mild ischemic stroke and explore the mechanism using an advanced post-processing method for magnetic resonance imaging. Methods: Seventy-six patients with acute mild ischemic stroke were recruited for this study and randomly divided into a grip training group (n = 37) and a control group (n = 39). Both groups of patients also received standardized treatment for stroke in the acute phase and for secondary prevention, as well as conventional physical therapy after stroke. Grip strength, global cognitive function, and the local and global efficiencies of white matter networks derived from diffusion tensor images were measured before and after the 12-week training period. Results: In the within-group comparisons, grip training significantly improved the grip strength (3.52 [3.09-3.96], p = 0.02), Montreal Cognitive Assessment (MoCA) (2.27 [1.68-2.86], p = 0.05), and local, but not global, efficiency of the brain white matter network (0.03 [0.02-0.03], p = 0.02) in the experimental group. In contrast, these parameters were not statistically different over the same period in the control group. In the between-groups comparisons, the improvement of grip strength (2.71 [2.20-3.21], p = 0.01), MoCA (1.17 [0.39-1.95], p = 0.05), and local efficiency (0.02 [0.01-0.03], p = 0.01) showed statistically significant differences after the intervention, but not the absolute value of them, neither at the base line nor after the intervention. Conclusions: Our results indicate that grip training can improve cognitive function by increasing the local efficiency of brain white matter connectivity. This suggests that white matter remodeling is a potential physiological mechanism connecting grip training and cognition improvement.