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NCT Number: NCT05341466

The Effect of Acute Intermittent Hypoxia on Motor Learning

The goal of this study is to examine the effect of repetitive acute intermittent hypoxia on motor learning abilities in able-bodied individuals for subsequent study in individuals with incomplete spinal cord injury.

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Key information

Conditions

Incomplete Spinal Cord Injury Central Nervous System Diseases Nervous System Diseases Spinal Cord Diseases Spinal Cord Injuries Trauma, Nervous System Wounds and Injuries

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Colorado, Anschutz Medical Campus, Aurora, Colorado, United States

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Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 18 to 70 years old (the latter to reduce likelihood of heart disease);
  • Medically stable with medical clearance from physician to participate;
  • Motor-incomplete spinal cord injuries at or below C2 and at or above L5;
  • AIS A-D at initial screen, or other non-traumatic spinal cord injury disorders (e.g. multiple sclerosis, ALS, tumors, acute transverse myelitis, etc.);
  • More than 1 year since iSCI to minimize confounds of spontaneous neurological recovery;
  • Ability to advance one step overground with or without assistive devices;

Exclusion criteria

  • Severe concurrent illness or pain;
  • Recurrent autonomic dysreflexia;
  • History of cardiovascular/pulmonary complications;
  • Concurrent physical therapy;
  • Pregnant at time of enrollment or planning to become pregnant;
  • Untreated painful musculoskeletal dysfunction, fracture or pressure sore;
  • History of seizures or epilepsy;
  • Recurring headaches;
  • Concussion within the last six months;
  • Depression or manic disorders
  • Metal implants in the head, or pacemaker.

Treatment and study plan

Acute Intermittent Hypoxia

Other

5 consecutive days of 15, 1.5 min episodes at 9% O2 (AIH) alternating with 21% O2 at 1 min intervals

Sham Acute Intermittent Hypoxia

Other

5 consecutive days of 15, 1.5 min episodes at 21% O2 (SHAM AIH) alternating with 21% O2 at 1 min intervals

Primary outcomes

  1. Change in Corticospinal Excitability

    Time frame: We will measure TMS before the start of 5 consecutive days of AIH or SHAM treatment. We will measure TMS within 24 hours of the final treatment.

    Transcranial magnetic stimulation (TMS) can be applied over the primary motor cortex to examine changes in corticospinal excitability. The downstream muscle activation can be recorded with surface EMG as a motor-evoked potential (MEP). The peak-to-peak MEP amplitude (mV) is as an index of corticospinal excitability.

    A randomized sequence of TMS intensities can be applied over the primary motor cortex, ranging from 90-140% of the participants' resting motor threshold (RMT). The mean MEP amplitude will be plotted against the corresponding stimulation intensity to produce the recruitment curve. The area under the recruitment curve is an additional index of corticospinal excitability (mV/% RMT).

  2. Step Length Asymmetry

    Time frame: We will compare asymmetry 15 minutes after the final AIH treatment to asymmetry following no treatment (control group).

    Step length asymmetry will be quantified as the ratio of the normalized difference in step lengths between the fast and slow legs during split-belt motor adaptation: (Fast leg - Slow leg step length) / (Fast leg + Slow leg step length).

  3. Step Time Asymmetry

    Time frame: We will compare asymmetry 15 minutes after the final AIH treatment to asymmetry following no treatment (control group).

    Step time asymmetry will be quantified as the ratio of the normalized difference in step times between the fast and slow legs during split-belt motor adaptation: (Fast leg - Slow leg step time) / (Fast leg + Slow leg step time).

  4. Net Metabolic Power

    Time frame: We will compare net metabolic power 15 minutes after the final AIH treatment to asymmetry following no treatment (control group).

    Using expired gas analyses, we will calculate net metabolic power by inputting steady-state values for V̇O₂ and V̇CO₂ into standard regression equations (W), subtracting resting values, and normalizing the result to each participant's body weight (kg).

Sponsors and collaborators

Lead sponsor

University of Colorado, Boulder

Other

Collaborators

  • Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
  • Medical University of South Carolina
  • University of Colorado, Denver

Registry information

Official study title

Examining the Relationship Between Changes in Corticospinal Excitability and Motor Learning After Acute Intermittent Hypoxia in Able-bodied Individuals for Subsequent Study in Individuals With Incomplete Spinal Cord Injury.

Important dates

Study start
2022
Primary completion
2025
Study completion
2025
First posted
Apr 22, 2022
Registry last updated
May 14, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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