Ischemic Conditioning as an Intervention to Improve Motor Function in Chronic Stroke

Study Overview
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Brief Summary
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The investigators will test whether an intervention called ischemic conditioning can improve paretic leg motor function in chronic stroke subjects.

Detailed Description
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This study will study ischemic conditioning (IC) as an intervention to improve motor function post-stroke. IC is a well studied, well tolerated intervention which has been shown to improve regional blood flow, motor neuron excitability and muscle function in multiple patient groups and in young, healthy subjects. Because IC targets three physiological systems which are all affected by stroke, the investigators hypothesize that repeated bouts of IC will result in improved motor function of the paretic leg.

Official Title
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Ischemic Conditioning as an Intervention to Improve Motor Function in Chronic Stroke

Conditions
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Stroke

Intervention / Treatment
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* Other: Ischemic Conditioning
* Other: Sham


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: be between the ages of 18-85 able to give informed consent be ≥ 6 months post diagnosis of unilateral cortical stroke and have residual leg paresis. Exclusion Criteria: chronic low back or hip pain substance abuse head trauma in last 6 months neurodegenerative disorder any uncontrolled medical condition any condition where knee extension contractions are contraindicated people who are unable to follow multi step commands. people who cannot walk ≥ 10 ft without physical assistance. history of major psychiatric disorder participant has had a myocardial infarction in the last year participant has uncontrolled hypertension participant is unable to contract knee muscles

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ischemic Conditioning<br>The investigators will perform ischemic conditioning on the paretic leg by inflating a blood pressure cuff to 225 mmHg to occlude blood flow to the leg for 5 minutes. This will be repeated for 5 cycles, with 5 minutes of rest between each cycle. The intervention will be performed for a maximum of 12 times within a 4 week period. | Other: Ischemic Conditioning<br>* Inflation of blood pressure cuff to 225 mmHg on paretic leg. 1 session: 5 minutes of inflation, 5 minutes deflation, repeated 5 times. Maximum 12 sessions over 4 weeks.<br>|
| Sham Comparator: Sham<br>The investigators will perform sham ischemic conditioning on the paretic leg by inflating a blood pressure cuff to only 25 mmHg on the leg for 5 minutes. This will be repeated for 5 cycles, with 5 minutes of rest between each cycle. The intervention will be performed for a maximum of 12 times within a 4 week period. | Other: Sham<br>* Inflation of blood pressure cuff to 25 mmHg on paretic leg. 1 session: 5 minutes of inflation, 5 minutes deflation, repeated 5 times. Maximum 12 sessions over 4 weeks.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Leg Muscle Strength | Maximum voluntary contraction of the leg muscles, measured in Newton Meters, as assessed using a Biodex dynamometer. | Within 1 year of admission into the study | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Leg Muscle Fatigue | Duration the leg muscles can sustain contraction to a load level equal to 30% of a maximum voluntary contraction. Measurement units will be seconds the contraction can be held, as assessed using a Biodex Dynamometer. | Within 1 year of admission into the study | 
| Brachial Artery Flow Mediated Dilation | Percent dilation of the brachial artery | Within 1 year of admission into the study |