Spinal Cord Injury (SCI)
Conditions
Keywords
acute intermittent hypoxia (AIH), spinal neuroplasticity, motor function, respiratory strength training, respiration, breathing, plasticity
Brief summary
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
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.
Interventions
OTHERDaily AIH Block
Daily sessions of AIH (dAIH) with use of short episodes of low oxygen (9% O2)
OTHERSham dAIH Block
Daily sessions of sham dAIH which includes breathing room air (21% O2)
OTHERRespiratory Strength Training Block
Respiratory strength training using a hand-held device that resists inspiration or expiration.
OTHERAIH + Strength Training Block
AIH followed by respiratory strength training.
Sponsors
United States Department of Defense
Brooks Rehabilitation
University of Florida
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Masking description
Participants and the clinical evaluator will be informed of possible interventions but will be blinded to the gas mixture (hypoxic vs normoxic air) used during each AIH intervention.
Intervention 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.
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in maximal inspiratory pressure | Baseline, Day 1, Day 6, Day 8, Day 15 | Maximal inspiratory pressure is a non-invasive measure of the maximal force achieved when breathing in against an occluded airway. |
| Change in maximal expiratory pressure | Baseline, Day 1, Day 6, Day 8, Day 15 | Maximal expiratory pressure is a non-invasive measure of the maximal force generated when breathing out against an occluded airway. |
Countries
United States
Outcome results
None listed