NCT05341466

The Effect of Acute Intermittent Hypoxia on Motor Learning

Completed NA Results posted Last updated 14 May 2025

What this trial tests

NA trial testing Acute Intermittent Hypoxia in Incomplete Spinal Cord Injury in 56 participants. Completed in 24 February 2025.

Timeline

27 May 2022

Primary endpoint
31 January 2025

24 February 2025

Quick facts

Lead sponsor	University of Colorado, Boulder
Phase	NA
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	double
Primary purpose	treatment
Enrollment	56
Start date	27 May 2022
Primary completion	31 January 2025
Estimated completion	24 February 2025
Sites	2 locations across United States

Drugs / interventions tested

• Acute Intermittent Hypoxia
• SHAM Acute Intermittent Hypoxia

Conditions studied

• Incomplete Spinal Cord Injury — all drugs for Incomplete Spinal Cord Injury →

Sponsor

University of Colorado, Boulder

Who can join

Adults 18 to 70, any sex, with Incomplete Spinal Cord Injury. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Change in Corticospinal Excitability Primary · 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.

Group	Value	95% CI
Repetitive Acute Intermittent Hypoxia	0.528	± 0.188
SHAM Acute Intermittent Hypoxia	0.132	± 0.188

Step Length Asymmetry Primary · 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).

Group	Value	95% CI
Repetitive Acute Intermittent Hypoxia	-0.052	± 0.023
Control Group	-0.0478	± 0.024

Step Time Asymmetry Primary · 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).

Group	Value	95% CI
Repetitive Acute Intermittent Hypoxia	0.0781	± 0.021
Control Group	0.0681	± 0.0252

Net Metabolic Power Primary · 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).

Group	Value	95% CI
Repetitive Acute Intermittent Hypoxia	3.87	± 0.397
Control Group	4.27	± 0.766

Sponsor's own description

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.

Publications & conference data

3 peer-reviewed publications reference this trial (live from Europe PMC):

1. Enhanced motor learning and motor savings after acute intermittent hypoxia are associated with a reduction in metabolic cost.
   Bogard AT, Hemmerle MR, Smith AC, Tan AQ. · · 2024 · cited 13× · PMID 37983629 · DOI 10.1113/jp285425
2. Intermittent hypoxia-induced enhancements in corticospinal excitability predict gains in motor learning and metabolic efficiency.
   Bogard AT, Hembree TG, Pollet AK, Smith AC, et al · · 2025 · cited 3× · PMID 39994358 · DOI 10.1038/s41598-025-90890-8
3. Adaptive mediolateral control during split-belt walking: Energetics of interlimb coordination and enhanced savings following acute intermittent hypoxia.
   Nyangau NM, Bogard AT, Pollet AK, Tan AQ. · · 2026 · PMID 41863535 · DOI 10.1113/ep093291