The Effect of Acute Intermittent Hypoxia on Motor Learning

Study Overview
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Brief Summary
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The goal of this pilot study is to examine the effect of repetitive acute intermittent hypoxia on motor learning in persons with chronic, incomplete spinal cord injury.

Official Title
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Examining the Relationship Between Changes in Corticospinal Excitability and Motor Learning After Acute Intermittent Hypoxia in Persons With Incomplete Spinal Cord Injury

Conditions
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Incomplete Spinal Cord Injury

Intervention / Treatment
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* Other: Acute Intermittent Hypoxia
* Other: SHAM Acute Intermittent Hypoxia


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 to 70 years old (the latter to reduce likelihood of heart disease); Medically stable with medical clearance from physician to participate; Motor-incomplete spinal cord injuries at or below C2 and at or above L5; AIS A-D at initial screen, or other non-traumatic spinal cord injury disorders (e.g. multiple sclerosis, ALS, tumors, acute transverse myelitis, etc.); More than 1 year since iSCI to minimize confounds of spontaneous neurological recovery; Ability to advance one step overground with or without assistive devices; Exclusion Criteria: Severe concurrent illness or pain; Recurrent autonomic dysreflexia; History of cardiovascular/pulmonary complications; Concurrent physical therapy; Pregnant at time of enrollment or planning to become pregnant; Untreated painful musculoskeletal dysfunction, fracture or pressure sore; History of seizures or epilepsy; Recurring headaches; Concussion within the last six months; Depression or manic disorders Metal implants in the head, or pacemaker.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Repetitive Acute Intermittent Hypoxia<br>5 consecutive days of 15, 1.5 min episodes at 9% O2 (AIH) alternating with 21% O2 at 1 min intervals | Other: Acute Intermittent Hypoxia<br>* 5 consecutive days of 15, 1.5 min episodes at 9% O2 (AIH) alternating with 21% O2 at 1 min intervals<br>|
| Sham Comparator: SHAM Acute Intermittent Hypoxia<br>5 consecutive days of 15, 1.5 min episodes at 21% O2 (SHAM AIH) alternating with 21% O2 at 1 min intervals | Other: SHAM Acute Intermittent Hypoxia<br>* 5 consecutive days of 15, 1.5 min episodes at 21% O2 (SHAM AIH) alternating with 21% O2 at 1 min intervals<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in the Transcranial Magnetic Stimulation Recruitment Curve Slope | The mean motor evoked potential response will be plotted against the corresponding stimulation intensity (% resting motor threshold) to produce a stimulus-response curve | We will measure TMS before the start of 5 consecutive days of AIH treatment. We will measure TMS within 24 hours of the final AIH treatment. | 
| Change in Step Length Asymmetry | Step length asymmetry will be quantified as the ratio of normalized difference in step lengths of each leg. | We will measure asymmetry before the start of 5 consecutive days of AIH treatment as baseline. We will measure asymmetry within 24 hours after the final AIH treatment. | 
| Change in Step Time Asymmetry | Step time asymmetry will be quantified as the ratio of normalized difference in step times of each leg | We will measure asymmetry before the start of 5 consecutive days of AIH treatment as baseline. We will measure asymmetry within 24 hours after the final AIH treatment. | 
| Change in Metabolic Power | Using expired gas analyses, the measured rates of V̇o2 and V̇co2, will be converted to metabolic power and normalized to each participant's body weight | We will measure metabolic power before the start of 5 consecutive days of AIH treatment as baseline. We will measure metabolic power within 24 hours after the final AIH treatment. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change Muscle Surface Electromyography | Muscle activation will be recording using surface EMG, and quantified as the activation amplitude and activation timing of the leg muscles during walking assessments. EMG amplitude will be normalized to maximum contraction during walking and activation will be normalized to the gait cycle. We will record EMG's of the muscles that contribute to ankle and knee joint torque production. | We will measure EMG during a baseline walking assessment before the start of 5 consecutive days of AIH treatment. We will measure EMG during a post walking assesment within 24 hours after the final AIH treatment. | 
| Change in Leg Kinematics | The relative ankle, knee, and hip joint angle excursions throughout the gait cycle will be quantified during walking assessments. | We will measure kinematics during a baseline walking assessment before the start of 5 consecutive days of AIH treatment. We will measure kinematics during a post walking assesment within 24 hours after the final AIH treatment. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Acuter Intermittent Hypoxia, Spinal Cord Injury, Motor Adaptation