Trial Outcomes & Findings for The Effect of Acute Intermittent Hypoxia on Motor Learning (NCT NCT05341466)
NCT ID: NCT05341466
Last Updated: 2025-05-14
Results Overview
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).
COMPLETED
NA
56 participants
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.
2025-05-14
Participant Flow
Individuals were recruited through advertisements in Colorado, with recruitment occurring from May 2022 through January 2025. A total of 56 participants were enrolled across both studies. Part 1: Motor Learning (N = 30) \& Part 2: Corticospinal Indices of Motor Learning (N = 26).
Participants were randomly assigned to their respective groups and completed either AIH, SHAM, or no treatment before undergoing motor learning assessments using a split-belt treadmill paradigm. Qualifying participants also received corticospinal excitability assessments using transcranial magnetic stimulation (TMS).
Participant milestones
| Measure |
Repetitive Acute Intermittent Hypoxia
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
5 consecutive days of 15, 1.5 min episodes at 21% O2 (SHAM AIH) alternating with 21% O2 at 1 min intervals
|
Control Group
No AIH or SHAM exposure
|
|---|---|---|---|
|
Overall Study
STARTED
|
28
|
13
|
15
|
|
Overall Study
COMPLETED
|
28
|
13
|
15
|
|
Overall Study
NOT COMPLETED
|
0
|
0
|
0
|
Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
The Effect of Acute Intermittent Hypoxia on Motor Learning
Baseline characteristics by cohort
| Measure |
Repetitive Acute Intermittent Hypoxia
n=28 Participants
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
n=13 Participants
5 consecutive days of 15, 1.5 min episodes at 21% O2 (SHAM AIH) alternating with 21% O2 at 1 min intervals
|
Control Group
n=15 Participants
No AIH or SHAM exposure
|
Total
n=56 Participants
Total of all reporting groups
|
|---|---|---|---|---|
|
Age, Categorical
<=18 years
|
0 Participants
n=85 Participants
|
1 Participants
n=18 Participants
|
2 Participants
n=39 Participants
|
3 Participants
|
|
Age, Categorical
Between 18 and 65 years
|
28 Participants
n=85 Participants
|
12 Participants
n=18 Participants
|
13 Participants
n=39 Participants
|
53 Participants
|
|
Age, Categorical
>=65 years
|
0 Participants
n=85 Participants
|
0 Participants
n=18 Participants
|
0 Participants
n=39 Participants
|
0 Participants
|
|
Sex: Female, Male
Female
|
16 Participants
n=85 Participants
|
6 Participants
n=18 Participants
|
8 Participants
n=39 Participants
|
30 Participants
|
|
Sex: Female, Male
Male
|
12 Participants
n=85 Participants
|
7 Participants
n=18 Participants
|
7 Participants
n=39 Participants
|
26 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
0 Participants
n=85 Participants
|
0 Participants
n=18 Participants
|
0 Participants
n=39 Participants
|
0 Participants
|
|
Race (NIH/OMB)
Asian
|
0 Participants
n=85 Participants
|
0 Participants
n=18 Participants
|
1 Participants
n=39 Participants
|
1 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=85 Participants
|
0 Participants
n=18 Participants
|
0 Participants
n=39 Participants
|
0 Participants
|
|
Race (NIH/OMB)
Black or African American
|
0 Participants
n=85 Participants
|
0 Participants
n=18 Participants
|
1 Participants
n=39 Participants
|
1 Participants
|
|
Race (NIH/OMB)
White
|
26 Participants
n=85 Participants
|
12 Participants
n=18 Participants
|
13 Participants
n=39 Participants
|
51 Participants
|
|
Race (NIH/OMB)
More than one race
|
2 Participants
n=85 Participants
|
1 Participants
n=18 Participants
|
0 Participants
n=39 Participants
|
3 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=85 Participants
|
0 Participants
n=18 Participants
|
0 Participants
n=39 Participants
|
0 Participants
|
PRIMARY outcome
Timeframe: 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.Population: A total of 56 participants were enrolled for this study: Part 1: Motor Learning (N = 30; AIH group + control group) \& Part 2: Corticospinal Indices of Motor Learning (N = 36; AIH group + SHAM group). Changes in corticospinal excitability reflect the results from Part 2 of the study, which consisted of an AIH group and a SHAM group (i.e., blinded normoxia).
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).
Outcome measures
| Measure |
Repetitive Acute Intermittent Hypoxia
n=13 Participants
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
n=13 Participants
5 consecutive days of 15, 1.5 min episodes at 21% O2 (SHAM AIH) alternating with 21% O2 at 1 min intervals
|
|---|---|---|
|
Change in Corticospinal Excitability
|
0.528 mV*percentage of RMT
Standard Error 0.188
|
0.132 mV*percentage of RMT
Standard Error 0.188
|
PRIMARY outcome
Timeframe: We will compare asymmetry 15 minutes after the final AIH treatment to asymmetry following no treatment (control group).Population: A total of 56 participants were enrolled for this study: Part 1: Motor Learning (N = 30; AIH group + control group) \& Part 2: Corticospinal Indices of Motor Learning (N = 36; AIH group + SHAM group). Changes in step length asymmetry reflect the results from Part 1 of the study, which consisted of an AIH group and a 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).
Outcome measures
| Measure |
Repetitive Acute Intermittent Hypoxia
n=15 Participants
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
n=15 Participants
5 consecutive days of 15, 1.5 min episodes at 21% O2 (SHAM AIH) alternating with 21% O2 at 1 min intervals
|
|---|---|---|
|
Step Length Asymmetry
|
-0.052 Ratio
Standard Deviation 0.023
|
-0.0478 Ratio
Standard Deviation 0.024
|
PRIMARY outcome
Timeframe: We will compare asymmetry 15 minutes after the final AIH treatment to asymmetry following no treatment (control group).Population: A total of 56 participants were enrolled for this study: Part 1: Motor Learning (N = 30; AIH group + control group) \& Part 2: Corticospinal Indices of Motor Learning (N = 36; AIH group + SHAM group). Changes in step time asymmetry reflect the results from Part 1 of the study, which consisted of an AIH group and a 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).
Outcome measures
| Measure |
Repetitive Acute Intermittent Hypoxia
n=15 Participants
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
n=15 Participants
5 consecutive days of 15, 1.5 min episodes at 21% O2 (SHAM AIH) alternating with 21% O2 at 1 min intervals
|
|---|---|---|
|
Step Time Asymmetry
|
0.0781 Ratio
Standard Deviation 0.021
|
0.0681 Ratio
Standard Deviation 0.0252
|
PRIMARY outcome
Timeframe: We will compare net metabolic power 15 minutes after the final AIH treatment to asymmetry following no treatment (control group).Population: A total of 56 participants were enrolled for this study: Part 1: Motor Learning (N = 30; AIH group + control group) \& Part 2: Corticospinal Indices of Motor Learning (N = 36; AIH group + SHAM group). Changes in net metabolic power reflect the results from Part 1 of the study, which consisted of an AIH group and a control group. One participant was excluded from metabolic analysis due to RER \> 1.0, violating assumption that primarily oxidative pathways were being utilized.
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).
Outcome measures
| Measure |
Repetitive Acute Intermittent Hypoxia
n=15 Participants
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
n=15 Participants
5 consecutive days of 15, 1.5 min episodes at 21% O2 (SHAM AIH) alternating with 21% O2 at 1 min intervals
|
|---|---|---|
|
Net Metabolic Power
|
3.87 W/kg
Standard Deviation 0.397
|
4.27 W/kg
Standard Deviation 0.766
|
Adverse Events
Repetitive Acute Intermittent Hypoxia
Control Group
SHAM Acute Intermittent Hypoxia
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place