Intermittent Hypoxia to Enhance Motor Function After Spinal Cord Injury

Study Overview
=================
Brief Summary
-----------------
This study will examine if acute intermittent hypoxia (brief episodes of breathing lower oxygen), which has been shown to enhance plasticity and motor output, can enhance functional outcomes and muscle activation in individuals with spinal cord injury. Our aim is to assess breathing, sitting, standing and walking functional ability before and after acute intermittent hypoxia, compared to a sham treatment. This information may be useful in advancing rehabilitation for people with spinal cord injuries.

Detailed Description
-----------------
Recent evidence has shown that acute intermittent hypoxia can strengthen motor pathways after spinal cord injury, and enhance walking outcomes after walking rehabilitation compared to walking rehabilitation alone. A single session of acute intermittent hypoxia has also been shown to temporarily enhance breathing and limb strength in people with spinal cord injury. Further evidence supports the hypothesis that acute intermittent hypoxia acts on all motor pathways, and thus can enhance the strength of most muscles in the body. Spinal cord injury affects the muscles that control respiration. Decreased respiratory muscle function can lead to diseases of the respiratory system, which are the primary cause of death and significant cause of re-hospitalization after spinal cord injury. Deficits in postural muscle function affect one's ability to balance, safely maintain a seated position, or ambulate after spinal cord injury, severely impacting daily activities such as self-care and feeding skills. This study will test the hypothesis that a single session of acute intermittent hypoxia will increase strength and activation of the muscles that control respiration and posture, leading to improved scores on functional assessments in individuals with chronic spinal cord injury. Our long term goal is to better understand the therapeutic potential of acute intermittent hypoxia combined with physical rehabilitation for individuals with chronic spinal cord injury.

Official Title
-----------------
Acute Intermittent Hypoxia to Enhance Motor Function After Spinal Cord Injury

Conditions
-----------------
Spinal Cord Injuries

Intervention / Treatment
-----------------
* Device: Hypoxia via Hypoxico Hyp-123
* Device: Sham via Hypoxico Hyp-123


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion criteria: Male or female, ages 18-65 Greater than 6 months post-spinal cord injury Spinal cord injury affecting segments between C4-T12 No other known neurological disorders Able to provide informed consent no severe musculoskeletal impairments, open wounds, or skin lesions that would limit participation in functional assessments. Exclusion criteria: Presence of a self-reported uncontrolled medical condition including, but not limited to: cardiovascular disease; sleep apnea; obstructive lung disease; severe neuropathic or chronic pain; severe recurrent autonomic dysreflexia Severe, untreated bladder or urinary tract infection Presence of severe musculoskeletal impairments, open wounds, or skin lesions that would limit participation in functional assessments Women who report being pregnant or test positive on a pregnancy test

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Acute Intermittent Hypoxia, then Sham Intermittent Hypoxia<br>Subjects with chronic spinal cord injury first received an acute intermittent hypoxia protocol with low oxygen air (9-15% inspired oxygen). After a washout period of at least one week, they then received sham intermittent hypoxia with normal oxygen air (21% inspired oxygen). | Device: Hypoxia via Hypoxico Hyp-123<br>* During acute intermittent hypoxia, subjects will undergo 15 brief exposures (60-120 seconds) of low oxygen air (9-15% inspired oxygen) delivered by an air generator, alternated with 15 brief exposures (60-120 seconds) of ambient room air.<br>* Other names: Altitude Generator;Device: Sham via Hypoxico Hyp-123<br>* During sham intermittent hypoxia, subjects will undergo 15 brief exposures (60-120 seconds) of normal oxygen air (21% inspired oxygen) delivered by an air generator, alternated with 15 brief exposures (60-120 seconds) of ambient room air.<br>* Other names: Altitude Generator;|
| Experimental: Sham Intermittent Hypoxia, then Acute Intermittent Hypoxia<br>Subjects with chronic spinal cord injury first received a sham (placebo) intermittent hypoxia protocol with normal oxygen air (21% inspired oxygen). After a washout period of at least one week, they then received an acute intermittent hypoxia protocol with low oxygen air (9-15% inspired oxygen). | Device: Hypoxia via Hypoxico Hyp-123<br>* During acute intermittent hypoxia, subjects will undergo 15 brief exposures (60-120 seconds) of low oxygen air (9-15% inspired oxygen) delivered by an air generator, alternated with 15 brief exposures (60-120 seconds) of ambient room air.<br>* Other names: Altitude Generator;Device: Sham via Hypoxico Hyp-123<br>* During sham intermittent hypoxia, subjects will undergo 15 brief exposures (60-120 seconds) of normal oxygen air (21% inspired oxygen) delivered by an air generator, alternated with 15 brief exposures (60-120 seconds) of ambient room air.<br>* Other names: Altitude Generator;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Maximal Inspiratory Pressure | An assessment of inspiratory muscle strength. | Change between baseline and 30 minutes post-intermittent hypoxia or sham. | 
| Change in Maximal Expiratory Pressure | An assessment of expiratory muscle strength. | Change between baseline and 30 minutes post-intermittent hypoxia or sham. | 
| Change in Forced Vital Capacity | An assessment of how much air a person can forcefully exhale after a maximal inspiratory effort. | Change between baseline and 30 minutes post-intermittent hypoxia or sham. | 
| Change in Mouth Occlusion Pressure (P0.1) | An assessment of the pressure generated in the first 0.1 seconds of the participant's initiation of inhalation. | Change between baseline and 30 minutes post-intermittent hypoxia or sham. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
acute intermittent hypoxia, breathing, spinal cord injury, motor function