Acute Intermittent Hypoxia on Leg Function Following Spinal Cord Injury
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|ClinicalTrials.gov Identifier: NCT02274116|
Recruitment Status : Recruiting
First Posted : October 24, 2014
Last Update Posted : March 29, 2018
The purpose of this study is to determine how the nervous system controlling leg muscles is altered following spinal cord injury and how they may be affected by brief periods of low oxygen inhalation over time.
The investigators hypothesize:
- Acute intermittent hypoxia (AIH) exposure will increase maximum voluntary leg strength in persons with incomplete cervical spinal cord injury (SCI)
- AIH exposure will increase multijoint reflex excitability of leg muscles in persons with incomplete cervical SCI
- AIH exposure will increase walking performance in persons with incomplete cervical SCI
|Condition or disease||Intervention/treatment||Phase|
|Spinal Cord Injuries||Other: SHAM - Intermittent Room Air - room air mixture Other: AIH - Intermittent Hypoxia - hypoxia air mixture||Not Applicable|
Accumulating evidence suggests that repeatedly breathing low oxygen levels for brief periods (termed intermittent hypoxia) is a safe and effective treatment strategy to promote meaningful functional recovery in persons with chronic spinal cord injury. Repetitive exposure to mild hypoxia triggers a cascade of events in the spinal cord, including new protein synthesis and increased sensitivity in the circuitry necessary for breathing and walking. Recently, the investigators demonstrated that daily (5 consecutive days) of intermittent hypoxia stimulated walking enhancement in persons with chronic spinal cord injury.
Despite these exciting findings, important clinical questions remain. For example, the investigators do not know if prolonged, but less intense intermittent hypoxia induces longer-lasting motor recovery as has been shown in rat models. The investigators hypothesize that repetitive exposures (3 times per week for 4 weeks) to modest bouts of low oxygen will enhance and prolong walking recovery in persons with chronic spinal cord injury. The investigators anticipate intermittent hypoxia-induced improvements in overground walking ability, likely due to greater balance in excitatory and inhibitory neural transmission. Whereas excitatory inputs drive walking, inhibitory inputs sculpt and coordinate muscle activity; yet so often remain compromised after chronic injury. Thus, the investigators also predict that repetitive exposures to intermittent hypoxia will result in improved inhibition and subsequently enhance muscle coordination during walking. The investigators will use multiple experimental approaches, including muscle electromyography, measurements of walking dynamics and stretch reflexes. Finally, it is critical to assure that repetitive exposures to intermittent hypoxia do not elicit pathologies characteristic of more severe, chronic hypoxia experienced by individuals with obstructive sleep apnea. The investigators will confirm that repeat exposures to mild bouts of intermittent hypoxia is safe.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||20 participants|
|Intervention Model:||Crossover Assignment|
|Masking:||Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)|
|Official Title:||Repetitive Exposure of Intermittent Hypoxia to Enhance Walking Recovery in Persons With Chronic Spinal Cord Injury|
|Study Start Date :||October 2014|
|Estimated Primary Completion Date :||May 2020|
|Estimated Study Completion Date :||August 2020|
Active Comparator: Intermittent Hypoxia (AIH)
Subjects with chronic, motor-incomplete SCI will breath mild bouts of low oxygen.
Intervention: AIH - Intermittent Hypoxia - hypoxia air mixture Dosage: 9% oxygen Frequency: 1.5 minutes bouts with 1.0 minute intervals Duration: 38 minutes
Other: AIH - Intermittent Hypoxia - hypoxia air mixture
Participants will breath intermittent low oxygen via air generators. The generators will fill reservoir bags attached to a non-rebreathing face mask. Oxygen concentration will be continuously monitored to ensure delivery of fraction of inspired oxygen (FIO2)=0.09±0.02 (hypoxia). Participants will receive treatment 3 times per week for 4 weeks.
Sham Comparator: Intermittent Room Air (SHAM)
Subjects with chronic, motor-incomplete SCI will breath mild bouts of room air.
Intervention: SHAM - Intermittent Room Air - room air mixture Dosage: 21% oxygen Frequency: 1.5 minutes bouts with 1.0 minute intervals Duration: 38 minutes
Other: SHAM - Intermittent Room Air - room air mixture
Participants will breath intermittent room air via air generators. The generators will fill reservoir bags attached to a non-rebreathing face mask. Oxygen concentration will be continuously monitored to ensure delivery of fraction of inspired oxygen (FIO2)=0.21±0.02 (normoxia). Participants will receive treatment 3 times per week for 4 weeks.
- Change in overground walking endurance [ Time Frame: Baseline, immediately following intervention (day 5), and at 1, 2, and 4 weeks ]walking endurance (6 minute walk test - how far one can walk in 6 minutes)
- Change in overground walking speed [ Time Frame: Baseline, immediately following intervention (day 5), and at 1, 2, and 4 weeks ]walking speed (10 meter walk test - how fast one can walk in 10 meters)
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02274116
|Contact: Randy D Trumbower, PT, PhDfirstname.lastname@example.org|
|Contact: Melissa DeChellisemail@example.com|
|United States, Massachusetts|
|Spaulding Rehabilitation Hospital||Recruiting|
|Cambridge, Massachusetts, United States, 02138|
|Contact: Randy D Trumbower, PT, PhD 617-952-6951 firstname.lastname@example.org|
|Contact: Melissa DeChellis (617) 952-6953 email@example.com|
|Principal Investigator:||Randy D Trumbower, PT, PhD||Spaulding Rehabilitation Hospital|