Reflex Excitability in Post-stroke Stiff-Knee Gait

Study Overview
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Brief Summary
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The purpose of this study is to examine the reflex excitability of the rectus femoris in individuals with and without post-stroke Stiff-Knee gait. We use electrical stimulation of the peripheral nerve innervating the rectus femoris for a well-controlled reflex stimulus. We are investigating whether reflex excitability of the rectus femoris correlates with gait kinematics.

Detailed Description
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The purpose of this study is to investigate the role of hyperreflexia in post-stroke Stiff-Knee gait function. In one aim,

Official Title
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Characterization of Abnormal Reflex Couplings Via H-reflex Stimulation

Conditions
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Stroke, Chronic Stroke, Gait, Hemiplegic, Gait, Spastic, Gait Disorder, Sensorimotor, Gait Disorders, Neurologic, Walking, Difficulty

Intervention / Treatment
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* Other: Peripheral nerve stimulation
* Device: Commercial knee brace


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Aged at least 18 Premorbidly independent If post-stroke, mild to moderate impairment determined by standard practices per the physical therapist Able to continuously walk for 30 minutes If post-stroke, reduced knee flexion during walking relative to unimpaired side If post-stroke, hemiparesis Ability to provide informed consent Exclusion criteria: No history of serious lower limb musculoskeletal injury No functionally relevant osteoarthritis and weight-bearing restrictions No functionally relevant polyneuropathy No functionally relevant cognitive impairment No functionally relevant vision impairment

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Post-stroke Stiff-Knee Gait Participants<br>Individuals with post-stroke Stiff-Knee gait | Other: Peripheral nerve stimulation<br>* Electrical stimulation of peripheral nerves to measure resulting gait kinematics and surface muscle activity<br>|
| Experimental: Healthy Individuals<br>Healthy Individuals | Other: Peripheral nerve stimulation<br>* Electrical stimulation of peripheral nerves to measure resulting gait kinematics and surface muscle activity<br>Device: Commercial knee brace<br>* Knee brace used to limit knee mobility in healthy individuals to imitate stroke survivors and measure resulting gait kinematics and surface muscle activity.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Surface electromyographic recording of leg muscles during different conditions | Recording electrical activity of leg muscles during walking in response to peripheral nerve stimulation | 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Circumduction measure | Hip abduction joint motion measured with motion capture | 1 hour |