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Acute Intermittent Hypoxia on Leg Function Following Spinal Cord Injury

This study is currently recruiting participants.
See Contacts and Locations
Verified July 2017 by Randy D. Trumbower, Emory University
Sponsor:
Collaborator:
Foundation Wings For Life
Information provided by (Responsible Party):
Randy D. Trumbower, Emory University
ClinicalTrials.gov Identifier:
NCT02274116
First received: October 6, 2014
Last updated: July 25, 2017
Last verified: July 2017
  Purpose

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 Intervention Phase
Spinal Cord Injuries Other: SHAM - Intermittent Room Air - room air mixture Other: AIH - Intermittent Hypoxia - hypoxia air mixture Phase 1 Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Repetitive Exposure of Intermittent Hypoxia to Enhance Walking Recovery in Persons With Chronic Spinal Cord Injury

Resource links provided by NLM:


Further study details as provided by Randy D. Trumbower, Emory University:

Primary Outcome Measures:
  • Change in overground walking speed [ Time Frame: Baseline, immediately following intervention, and at follow-ups (4 months) ]
  • Change in overground walking endurance [ Time Frame: Baseline, immediately following intervention, and at follow-ups (4 months) ]

Secondary Outcome Measures:
  • Change in muscle coordination [ Time Frame: Baseline, immediately following intervention, and at follow-ups (4 months) ]
  • Change in strength of muscle spanning the leg [ Time Frame: Baseline, immediately following intervention, and at follow-ups (4 months) ]
  • Change in reflex excitability (spasticity) of muscles spanning the leg [ Time Frame: Baseline, immediately following intervention, and at follow-ups (4 months) ]

Estimated Enrollment: 20
Study Start Date: October 2014
Estimated Study Completion Date: August 2020
Estimated Primary Completion Date: May 2019 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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 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 FIO2=0.21±0.02 (normoxia). Participants will receive treatment 3 times per week for 4 weeks.

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 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.

  Eligibility

Ages Eligible for Study:   18 Years to 77 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • 18 to 77 years old (the latter to reduce likelihood of heart disease);
  • medically stable with clearance from physician to participate;
  • motor--‐incomplete SCI at C4--‐T12 with non--‐progressive etiology;
  • >1 year since SCI to ensure minimal confounds of spontaneous neurological recovery;
  • ability to advance one step overground without human assistance.

Exclusion Criteria:

  • concurrent illness, including unhealed decubiti, severe neuropathic or chronic pain syndrome, infection, cardiovascular disease, osteoporosis (history of fractures), active heterotopic ossification, or known history of peripheral nerve injury to legs;
  • less than 24 on the Mini-mental Exam;
  • recurrent autonomic dysreflexia
  • cardiopulmonary complications
  • concurrent physical therapy
  • pregnancy because of unknown effects of AIH on a fetus, although women will not otherwise be excluded
  • severe obstructive sleep apnea (OSA), characterized by uncontrolled hypoxia and sleep fractionation that may impact the outcome of this study due to cardiovascular comorbidities. To screen for OSA, we will monitor the subject's oxygen saturation during one night of sleep with a portable pulse oximeter that records up to 10 continuous hours of heart rate (HR), respiration rate (RR), and oxygen saturation (SpO2) Persons with > 30 apneas and hypopneas per hour of sleep will be excluded.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT02274116

Contacts
Contact: Randy D Trumbower, PT, PhD 404-712-5985 randy.trumbower@emory.edu
Contact: Denise Peters, PT, PhD 404-712-5985 labtrumbower@gmail.com

Locations
United States, Georgia
Emory Rehabilitation Hospital Recruiting
Atlanta, Georgia, United States, 30322
Contact: Randy D Trumbower, PT, PhD    404-727-3065    randy.trumbower@emory.edu   
Contact: Denise Peters, PhD    404-712-5985    labtrumbower@gmail.com   
Principal Investigator: Randy D Trumbower, PT, PhD         
Sponsors and Collaborators
Emory University
Foundation Wings For Life
Investigators
Principal Investigator: Randy D Trumbower, PT, PhD Emory University
  More Information

Publications:
Responsible Party: Randy D. Trumbower, Assistant Professor, Emory University
ClinicalTrials.gov Identifier: NCT02274116     History of Changes
Other Study ID Numbers: IRB00044670
Study First Received: October 6, 2014
Last Updated: July 25, 2017

Keywords provided by Randy D. Trumbower, Emory University:
acute intermittent hypoxia
walking
spasticity
incomplete spinal cord injury
breathing
strength

Additional relevant MeSH terms:
Wounds and Injuries
Spinal Cord Injuries
Anoxia
Spinal Cord Diseases
Central Nervous System Diseases
Nervous System Diseases
Trauma, Nervous System
Signs and Symptoms, Respiratory
Signs and Symptoms

ClinicalTrials.gov processed this record on August 21, 2017