NCT02323945

Effects of Breathing Mild Bouts of Low Oxygen on Limb Mobility After Spinal Injury

Mechanisms of Intermittent Hypoxia-induced Motor Recovery in Persons With SCI

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 44 (estimated)
• Sponsor: Spaulding Rehabilitation Hospital · Academic / Other
• Sex: All
• Age: 18 Years – 75 Years
• Healthy volunteers: Accepted

Summary

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 (SCI). The goal of the study is to understand the mechanisms by which intermittent hypoxia enhances motor function and spinal plasticity (ability of the nervous system to strengthen neural pathways based on new experiences) following SCI.

Detailed description

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 questions remain. First, does intermittent hypoxia improve walking recovery by increasing strength or muscle coordination or both? Understanding its mechanisms will allow us to best apply intermittent hypoxia in the clinic. Second, initial studies indicate that the beneficial effects of intermittent hypoxia are greatest when intermittent hypoxia is used just prior to task training and that the benefits are greatest for the practiced task. The investigators will explore this possibility by examining the effects of intermittent hypoxia on walking ability and force production when applied alone and when applied in combination with walking training or strength training. The investigators expect to observe the greatest improvements in walking ability in those individuals receiving intermittent hypoxia with walking training and the greatest improvements in strength in response to intermittent hypoxia with strength training. Third, studies suggest that intermittent hypoxia induces spinal plasticity by increasing the expression of a key plasticity-promoting protein, brain-derived neurotrophic factor (BDNF). Mutations in the BDNF gene have been shown to impair BDNF functionality. Thus, the investigators will also explore the impact of BDNF polymorphisms on responsiveness to intermittent hypoxia therapy.

Conditions

• Spinal Cord Injuries

Interventions

Type	Name	Description
OTHER	AIH	Participants will breathe 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) = 0.10±0.02 (hypoxia). Participants will receive treatment on 5 consecutive days.
OTHER	Walk	30 minutes of walking practice consisting of 5 repetitions of 6-minute walks
OTHER	Strength	30 minutes of isometric ankle plantar flexion torque practice broken into 3 sets of 10 repetitions

Timeline

• Start date: 2014-10-01
• Primary completion: 2027-08-01
• Completion: 2027-11-01
• First posted: 2014-12-24
• Last updated: 2026-03-20

Locations

1 site across 1 country: United States