Treadmill exercise activates subcortical neural networks and improves walking after stroke: a randomized controlled trial.
OBJECTIVE
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.
Luft
Andreas R
AR
Department of General Neurology, University of Maryland, School of Medicine, Baltimore, MD, USA. aluft@jhu.edu
Macko
Richard F
RF
Forrester
Larry W
LW
Villagra
Federico
F
Ivey
Fred
F
Sorkin
John D
JD
Whitall
Jill
J
McCombe-Waller
Sandy
S
Katzel
Leslie
L
Goldberg
Andrew P
AP
Hanley
Daniel F
DF