Treadmill Exercise Activates Subcortical Neural Networks and Improves Walking After Stroke

Abstract

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 (nϭ37) versus comparable duration stretching (CON, nϭ34) on walking, aerobic fitness and in a subset (nϭ15/17) on brain activation measured by functional MRI. Results-T-EX significantly improved treadmill-walking velocity by 51% and cardiovascular fitness by 18% (11% and Ϫ3% for CON, respectively; PϽ0.05). 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 (PϽ0.005). 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. (Stroke. 2008;39:3341-3350.)

Plasticity in the developing brain: Implications for rehabilitation

“…However, fMRI scanning showed that BATRAC therapy was associated with greater activation of the cerebellum, ipsilateral precentral gyrus, and the contralateral hemisphere compared to controls, and there was an association between the fMRI response and clinical improvement. In contrast, another randomized controlled trail of task-related treadmill exercise alone in adult patients with chronic hemiparesis due to stroke showed improved walking and cardiovascular fitness and greater activation in fMRI compared to control therapy in the cerebellum and midbrain only [Luft et al, 2008]. Taken together, these results indicate that functional and structural imaging is providing objective data to consider alongside functional outcomes in assessing the effects of therapies on brain plasticity.…”

High-Intensity Interval Training Versus Moderate-Intensity Continuous Training in the Prevention/Management of Cardiovascular Disease

“…43 The fact that the total duration of MICT has been at least 8 weeks among the studies that found positive effects on VO2peak may also support this notion. 97,98,100,101,[103][104][105][106][107][108][109][110] On the other hand, the application of HIIT in stroke rehabilitation appears to be sparse Given that exercise prescriptive variables were similar between studies (4 x 4-minute work 13 periods at an intensity between 85 -95% of peak heart rate, interspersed with 3-minute rest periods), one may speculate that inter-study differences in subject characteristics The underlying mechanisms for the HIIT-and MICT-mediated improvement in VO2peak in those with stroke remain to be determined but could perhaps be attributable to an enhanced ability of the skeletal muscles to utilize O2 via improved mitochondrial function. 100 However, in view of the current literature, the use of MICT appears to be more promising than HIIT for improving aerobic fitness and health outcomes among stroke patients.…”

Bilateral Transcutaneous Electrical Nerve Stimulation Improves Lower‐Limb Motor Function in Subjects With Chronic Stroke: A Randomized Controlled Trial

“…The TOT protocol for this study was adopted from that in our previous study,4, 5 which demonstrated that a combination of placebo‐TENS and TOT outperformed a control group with no active treatment in isometric pDF and pPF strength4 and TUG completion time 5. The improvement in muscle strength after TOT could be attributed to an increase in muscle volume56 and recruitment of alternative neural substrate 57. Ryan and colleagues reported that 12 weeks of resistive training of the knee extensors increased the paretic thigh's cross‐sectional area and volume by ≈15% and increased the knee extension strength by 56% 56.…”