Treadmill exercise activates subcortical neural networks and improves walking after a stroke

• Main Authors: Luft, A.R (Author), Macko, R.F (Author), Forrester, L.W (Author), Villagra, F. (Author), Ivey, F. (Author), Sorkin, J.D (Author), Whitall, Jill (Author), McCombe-Waller, S. (Author), Katzel, L. (Author), Goldberg, A.P (Author), Hanley, D.F (Author)
• Format: Article
• Language: English
• Published: 2008-12.
• Subjects: Article
• Online Access: Get fulltext; Get fulltext

BACKGROUND AND PURPOSE: Stroke often impairs gait thereby reducing mobility and fitness and promoting chronic disability. Gait is a complex sensorimotor function controlled by integrated cortical, subcortical, and spinal networks. The mechanisms of gait recovery after stroke are not well understood. This study examines the hypothesis that progressive task-repetitive treadmill exercise (T-EX) improves fitness and gait function in subjects with chronic hemiparetic stroke by inducing adaptations in the brain (plasticity). METHODS: A randomized controlled trial determined the effects of 6-month T-EX (n=37) versus comparable duration stretching (CON, n=34) on walking, aerobic fitness and in a subset (n=15/17) on brain activation measured by functional MRI. RESULTS: T-EX significantly improved treadmill-walking velocity by 51% and cardiovascular fitness by 18% (11% and -3% for CON, respectively; P<0.05). T-EX but not CON affected brain activation during paretic, but not during nonparetic limb movement, showing 72% increased activation in posterior cerebellar lobe and 18% in midbrain (P<0.005). Exercise-mediated improvements in walking velocity correlated with increased activation in cerebellum and midbrain. CONCLUSIONS: T-EX improves walking, fitness and recruits cerebellum-midbrain circuits, likely reflecting neural network plasticity. This neural recruitment is associated with better walking. These findings demonstrate the effectiveness of T-EX rehabilitation in promoting gait recovery of stroke survivors with long-term mobility impairment and provide evidence of neuroplastic mechanisms that could lead to further refinements in these paradigms to improve functional outcomes.