Stimulation to Enhance Walking Post-SCI

Study Overview
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Brief Summary
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This study will investigate the effects of transcutaneous direct current stimulation (tsDCS) on walking function in individuals with incomplete spinal cord injury. Following rehabilitation, individuals with ISCI often demonstrate improved walking function, but continue to have serious impairments that limit mobility, community participation and quality of life. Adjuvants to rehabilitation that increase spinal excitation during training may enhance its effectiveness. tsDCS is a non-invasive neuromodulation approach that uses a mild electrical current, applied over the skin of the low back, to alter the membrane potential of spinal neurons. tsDCS will be applied during locomotor training, a well-established rehabilitation strategy that promotes walking recovery. Locomotor training emphasizes repetitive and task-specific practice of coordinated walking, often with therapist assistance or cueing to promote high quality movement patterns. The study team will explore if tsDCS combined with locomotor training increases spinal excitation and thereby improves the effectiveness of walking rehabilitation.

Detailed Description
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The purpose of this study is to investigate the effects of transcutaneous direct current stimulation (tsDCS) on locomotor function and rehabilitation outcomes in individuals with incomplete spinal cord injury (ISCI). tsDCS is a mild, non-invasive form of electrical stimulation that can alter spinal cord excitability. Specific Aim 1 (Cross-sectional): To test the hypothesis that tsDCS applied during walking will improve motor activation in adults with chronic ISCI. A random order, double blind cross-over study will be conducted across two test sessions to compare the immediate effects of two dosages of tsDCS during walking. To assess motor activation, the primary outcome measure will be lower extremity surface electromyography. Specific Aim 2 (Interventional): To test the hypothesis that tsDCS applied during 16 sessions of locomotor training will improve functional walking outcomes. Participants will be randomized to receive 16 sessions of locomotor training with one of the two tsDCS dosages. The primary outcome is walking function as measured by standardized clinical tests of walking speed and endurance. To address the aims of the study, the investigators will use a two-part study design. Following phone and in-person screenings and physician approval, individuals will provide informed consent to the study procedures. In the first part, participants will complete two separate testing sessions, presented in random order, that involve up to 30 minutes of tsDCS at one of two dosages levels while walking. The researchers will assess changes in motor activation before and at the end of the period of walking. For the second part, participants will be randomized to receive 16 sessions of locomotor training with one of the two dosages of tsDCS. Before and after the 16-session intervention (i.e., at baseline and post intervention), the study team will assess functional outcomes through standardized tests of walking speed and endurance.

Official Title
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Transcutaneous Spinal Direct Current Stimulation to Enhance Locomotion After Spinal Cord Injury

Conditions
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SCI - Spinal Cord Injury, Incomplete Spinal Cord Injury

Intervention / Treatment
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* Device: Soterix Medical tsDCS stimulator
* Other: Locomotor training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Single spinal cord injury (duration >1 year) classified as neurologic level T12 or above based on the International Standards for the Neurologic Classification of Spinal Cord Injury, and classified on the American Spinal Cord Injury Association (ASIA) Impairment Scale (AIS) as 'C' or 'D' motor incomplete Capable of ambulating 10 feet with or without the use of gait devices, braces, or the assistance of one person Medically stable with no acute illness or infection Able to provide informed consent Exclusion Criteria: Current diagnosis of an additional neurologic condition such as multiple sclerosis, Parkinson's disease, stroke, or brain injury Presence of unstable or uncontrolled medical conditions such as cardiovascular disease, myocardial infarction (<1 year), pulmonary infection or illness, renal disease, autonomic dysreflexia, infections, pain, heterotopic ossification Cognitive or communication impairments limiting communication with study staff or ability to provide informed consent Lower extremity joint contractures limiting the ability to stand upright and practice walking Skin lesions or wounds affecting participation in walking rehabilitation Acute or unstable fracture, diagnosis of osteoarthritis or bone impairments affecting safe participation in walking rehabilitation Severe spasticity or uncontrolled movements limiting participation in walking rehabilitation Body weight or height that is incompatible with safe use of a support harness and body weight support system Pain that limits walking or participation in walking rehabilitation Current participation in rehabilitation to address walking function Botox injections in lower extremity muscles affecting walking function within 4 months of study enrollment Legal blindness or severe visual impairment Known pregnancy Implanted metal hardware below the level of the 8th thoracic vertebrae

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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: Immediate effects<br>All participants will complete 2 sessions of walking with tsDCS separated by at least 72 hours. The only difference between sessions will be the dosage of stimulation (higher or lower dosage tsDCS using the Soterix Medical tsDCS stimulator). During each session, participants will be asked to walk for up to 30 minutes on a treadmill while the stimulation is delivered. Assessments will be completed before and after the bout of treadmill walking. | Device: Soterix Medical tsDCS stimulator<br>* tsDCS will be delivered to the lumbar region of the spinal cord with electrodes placed over the low back and abdomen. The electrodes will be secured with a large elastic bandage so that stimulation can be applied for up to 30 minutes during locomotor training with a harness attached to the ceiling for safety. A physical therapist will supervise the session.<br>|
| Experimental: Interventional effects: Higher dosage<br>After completing the 2 sessions of the first part of the study, the participants will be randomized to two groups for the second part of the study. Those in the higher dosage group will receive 16 sessions of locomotor training with tsDCS stimulation applied at the higher dosage for up to 30 minutes using the Soterix Medical tsDCS stimulator. The training sessions will be scheduled 4 days per week for 4 weeks. All training will be overseen by a physical therapist with experience in SCI walking rehabilitation and will involve the use of an overhead support harness. | Device: Soterix Medical tsDCS stimulator<br>* tsDCS will be delivered to the lumbar region of the spinal cord with electrodes placed over the low back and abdomen. The electrodes will be secured with a large elastic bandage so that stimulation can be applied for up to 30 minutes during locomotor training with a harness attached to the ceiling for safety. A physical therapist will supervise the session.<br>Other: Locomotor training<br>* Participants will complete 16 sessions of locomotor training (4 times per week for 4 weeks). This involves walking on a treadmill for up to 30 minutes with a harness attached to the ceiling for safety, followed by 10 minutes of overground walking training; with physical assistance as needed.<br>|
| Active Comparator: Interventional effects: Lower dosage<br>After completing the 2 sessions of the first part of the study, the participants will be randomized to two groups for the second part of the study. Those in the lower dosage group will receive 16 sessions of locomotor training with tsDCS stimulation applied at the lower dosage for up to 30 minutes using the Soterix Medical tsDCS stimulator. The training sessions will be scheduled 4 days per week for 4 weeks. All training will be overseen by a physical therapist with experience in SCI walking rehabilitation and will involve the use of an overhead support harness. | Device: Soterix Medical tsDCS stimulator<br>* tsDCS will be delivered to the lumbar region of the spinal cord with electrodes placed over the low back and abdomen. The electrodes will be secured with a large elastic bandage so that stimulation can be applied for up to 30 minutes during locomotor training with a harness attached to the ceiling for safety. A physical therapist will supervise the session.<br>Other: Locomotor training<br>* Participants will complete 16 sessions of locomotor training (4 times per week for 4 weeks). This involves walking on a treadmill for up to 30 minutes with a harness attached to the ceiling for safety, followed by 10 minutes of overground walking training; with physical assistance as needed.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in 10-Meter Walk Test (Interventional) | Performance assessment of comfortable and fastest safe walking speed for 10 meters. A reduced time (in seconds) to complete the 10-Meter Walk Test reflects improvement in walking function. | Baseline; Week 4 | 
| Change in Electromyogram (EMG; Immediate) | EMG will be used to assess the neuromuscular activation of the lower extremity muscles. A wireless, 16-channel EMG system will be applied at various key muscle groups on both lower extremities. Greater amplitude or changes in activation timing in the EMG signal will reflect improvement in muscle activation. | Baseline; 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in 6-Minute Walk Test (Interventional) | The 6-Minute Walk Test (6 MWT) is a submaximal exercise test that entails measurement of distance walked over a span of 6 minutes. An increase in the number of meters walked during this assessment reflects an improvement in walking endurance. | Baseline; Week 4 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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walking, locomotor training, rehabilitation