CUped: An Approach to Motor Recovery Post-Stroke, Not Compensation
The goal of lower limb rehabilitation after stroke is recovery of independent walking at home and in the community. Few stroke survivors achieve this goal. Suboptimal outcomes are due to the serious and intransigent nature of movement impairments caused by stroke and the scarcity of feasible and effective therapies that restore movement lost to stroke. Our team has developed a novel exercise intervention called CUped (pronounced cupid, like the Roman god) to address barriers to recovery and improve walking after stroke. CUped is so called because it compels use of the paretic limb during a movement that resembles pedaling. This project will examine safety, acceptability, and tolerance to CUped, characterize its therapeutic effects, and identify dose-response relationships. Results will provide preliminary data for an R01 to support a randomized controlled trial (RCT). CUped is designed to help stroke survivors recover lower limb movement lost to stroke, thereby improving walking. It is intended to be used as an adjunct to gait training. CUped uses a robotic technology that eliminates compensatory movements that interfere with recovery, compels use of the paretic lower limb, and targets 3 key movement impairments caused by stroke: decreased muscle output from the paretic limb, inappropriate paretic muscle timing, and abnormal interlimb coordination. Exercise is done in sitting which enables high repetition practice. Like walking, CUped requires continuous, reciprocal use of both lower limbs; effects are likely to transfer to walking. The risk-reward profile of this proposal is ideal for an R21, which is an NIH funding opportunity intended to encourage exploratory/developmental research by providing support for the early and conceptual stages of project development. CUped is a novel therapy grounded in a physiologic premise and based on prior observations from our laboratory. The investigators have pilot data suggesting that CUped fulfills its design specifications, and this study will be the first to test its therapeutic effects. In this Stage 1 rehabilitation trial, The investigators will support or quickly refute the hypothesis that CUped is safe, acceptable, and capable of eliciting a therapeutic response in stroke survivors. The investigators will also examine tolerance to CUped and dose-response effects. If our hypotheses are supported, the investigators will be poised to run an RCT to isolate the effects of CUped and compare them to standard care. Future work will investigate physiologic mechanisms underlying the effects of CUped.
• Single, unilateral stroke in adulthood.
• Cortical, subcortical stroke. Individuals with cortical lesions affecting sensory and motor structures in the gray matter of the brain will be included. Individuals subcortical white matter lesions affecting the internal capsule and corona radiata will be included.
• Ischemic, hemorrhagic stroke. Individuals with ischemic and hemorrhagic strokes will be admitted. Because ischemic stroke is more common than hemorrhagic, the investigators expect a smaller proportion of volunteers from the latter group.
• Chronic stroke. Individuals with chronic stroke, defined as \>6 months post infarct, will be included.
• Able to walk 10 m. Stroke survivors capable of walking 10 m overground will be admitted. Canes, walkers, braces, and other devices will be allowed. This study examines the effect of CUped on gait kinematics and kinetics; therefore, the ability to walk is imperative.
• Unilateral motor impairment consistent with hemiparesis.
• Learned non-use of the paretic limb. Non-use will be verified by comparing paretic limb work (W) during unilateral and bilateral coupled pedaling. Participants with non-use will be identified as those who produce significantly \<50% of the total W of bilateral coupled pedaling with their paretic limb but are capable of unilateral pedaling with the paretic limb at a workload equivalent to 50% of the total W of bilateral coupled pedaling. (Significance will be determined using a 1-sample t-test or corresponding non-parametric test in the case of non-normality).
• No contraindications for exercise. Contraindications to exercise include but may not be limited to recent electrocardiogram changes or recent myocardial infarction, uncontrolled arrhythmia, unstable angina, third degree heart block, acute progressive heart failure, uncontrolled hypertension, and orthopedic conditions (e.g., severe muscle contracture, arthritis, acute limb injury) that may interfere with pedaling.
• Age ≥18. All participants must be at least 18 years of age. The investigators are studying adult not childhood stroke. Recovery mechanisms are different between adult and childhood stroke survivors.
• Able to commit to 27 visits to the lab (pre-, mid-, post-test, plus 24 training sessions).