FLO2 for Recovery After SCI

Study Overview
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Brief Summary
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Acute intermittent hypoxia (AIH) involves short ( 1-2min) bouts of breathing low oxygen air to stimulate spinal neuroplasticity. Studies in rodents and humans indicate that AIH improves motor function after spinal cord injury (SCI). This study will use a double blind, cross-over design to test if the combination of AIH and respiratory strength training improves breathing function more than either approach alone in adults with chronic SCI.

Detailed Description
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Spinal cord injury (SCI) disrupts neural pathways to respiratory motor neurons, causing muscle paralysis and decreased breathing capacity. Since respiratory impairment is the major cause of illness and death with SCI, it is critical to devise new strategies to restore breathing function. Repetitive exposure to brief episodes of low oxygen (acute intermittent hypoxia or AIH) has demonstrated to increase respiratory function in humans with chronic SCI. Additionally pre-clinical studies demonstrate that AIH-induced functional benefits are enhanced by combining AIH with task-specific training. The investigator's central hypothesis is that combined daily AIH (dAIH) and respiratory strength training will elicit greater and more sustained gains in respiratory function than either treatment alone in people with chronic SCI. This study is a double-blind, randomized, cross-over design where participants will complete 4 random-ordered blocks, consisting of a 5-day intervention followed by a 3-week washout period, during which 1-day, 3-day, and 1-week post-tests will be conducted. Participants will include 53 adults with chronic, incomplete SCI with >20% respiratory impairment based on maximal inspiratory or expiratory pressure generation.

Official Title
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Acute Intermittent Hypoxia and Respiratory Strength Training to Improve Breathing Function After Spinal Cord Injury

Conditions
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Spinal Cord Injury (SCI)

Intervention / Treatment
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* Other: Daily AIH Block
* Other: Sham dAIH Block
* Other: Respiratory Strength Training Block
* Other: AIH + Strength Training Block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Chronic incomplete SCI for ≥ 1 year at or below C-1 to T-12 Incomplete SCI based on residual sensory and motor function below the level of the injury or injury classification of B, C, D at initial screening according to the American Spinal Injury Association Impairment Classification and the International Standards for the Neurological Classification of SCI -OR- Chronic complete SCI for ≥ 1 year at or below C-4 to T-12 Complete SCI based on the absence of residual sensory or motor function below the level of injury or injury classification of A at initial screening according to the American Spinal Injury Association Impairment Classification and the International Standards for the Neurological Classification of SCI. Medically stable with clearance from physician SCI due to non-progressive etiology >20% impairment in maximal inspiratory or expiratory pressure generation, relative to established normative values. 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 lung disease, infections, hypertension, heterotopic ossification. Severe neuropathic pain Known pregnancy Severe recurrent autonomic dysreflexia History of seizure disorder < 1 year

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Interventional Model Description: Participants will complete a battery of clinical assessments and 4 randomly ordered intervention and testing blocks. Blocks 1, 2 and 3 include a 5 day intervention (e.g., dAIH and/or respiratory training) or sham protocol, followed by a 3-week washout period, with follow up measurements at 1 day, 3 days and 1 week post-intervention. The final block includes a 5-day protocol followed by 1-day, 3-day and 1-week post-tests.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Adults with incomplete SCI<br>Adults with chronic, incomplete SCI who have >20% impairment in respiratory function, who will complete a battery of clinical assessments and 4 randomly ordered intervention and testing blocks (Daily AIH Block, Sham dAIH Block, Respiratory Strength Training Block and AIH + Strength Training Block). | Other: Daily AIH Block<br>* Daily sessions of AIH (dAIH) with use of short episodes of low oxygen (9% O2)<br>* Other names: dAIH Block;Other: Sham dAIH Block<br>* Daily sessions of sham dAIH which includes breathing room air (21% O2)<br>Other: Respiratory Strength Training Block<br>* Respiratory strength training using a hand-held device that resists inspiration or expiration.<br>Other: AIH + Strength Training Block<br>* AIH followed by respiratory strength training.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in maximal inspiratory pressure | Maximal inspiratory pressure is a non-invasive measure of the maximal force achieved when breathing in against an occluded airway. | Baseline, Day 1, Day 6, Day 8, Day 15 | 
| Change in maximal expiratory pressure | Maximal expiratory pressure is a non-invasive measure of the maximal force generated when breathing out against an occluded airway. | Baseline, Day 1, Day 6, Day 8, Day 15 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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acute intermittent hypoxia (AIH), spinal neuroplasticity, motor function, respiratory strength training, respiration, breathing, plasticity