Acute Intermittent Hypoxia Combined With Gait Training in Multiple Sclerosis

N/ANot Yet RecruitingNCT07631923

Shirley Ryan AbilityLab35 enrolled

Overview

This interventional, randomized, sham-controlled study will examine whether Acute Intermittent Hypoxia (AIH) delivered immediately before Myoelectric Interface Neurorehabilitation Training (MINT)-based locomotor training improves gait in people with Multiple Sclerosis. The primary objectives are to evaluate changes in gait speed and endurance, with secondary objectives assessing spatiotemporal gait parameters, fatigue, and safety. Participants will receive AIH or sham priming followed by standardized treadmill and/or overground gait training, with outcome measures collected before and after the intervention across multiple sessions.

The study tests whether a brief breathing treatment, acute intermittent hypoxia (AIH), can make a computer-based muscle training program (MINT) more effective for people with MS who have difficulty walking. AIH involves breathing short alternating periods of low-oxygen air (about 9% oxygen versus the roughly 21% in room air) and normal room air. The premise, drawn from work in other neurological conditions like spinal cord injury, is that AIH delivered before movement training may improve strength and walking. Whether this benefits people with MS is not yet known, which is the gap the study addresses. MINT itself uses surface EMG sensors on the leg muscles to capture muscle activity, which then controls game-like tasks on a screen. Participants practice activating the correct muscles for walking while suppressing unwanted activity.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Enrollment

Conditions

Multiple Sclerosis

Interventions

Acute Intermittent Hypoxia (AIH)OTHER

During AIH, the participant will be equipped with a non-rebreathing face mask, and provided with the AIH intervention. The AIH intervention involves alternating breathing cycles. One cycle involves breathing air with lower oxygen concentration (9-10% oxygen) for 30 and 90 seconds, followed by breathing normal room air (21% oxygen) for a similar duration. This cycle is repeated 15 times in one session. Blood oxygen and heart rate are monitored throughout.

Sham Acute Intermittent Hypoxia (AIH)OTHER

During Sham AIH, the participant will be equipped with a non-rebreathing face mask, and provided with the AIH intervention. The Sham AIH intervention involves alternating breathing cycles. One cycle involves breathing air closely resembling room air (\~21% oxygen) for 30 and 90 seconds, followed by breathing normal room air (21% oxygen) for a similar duration. This cycle is repeated 15 times in one session. Blood oxygen and heart rate are monitored throughout.

Myoelectric Interface Neurorehabilitation Training (MINT)OTHER

MINT is a gamified rehabilitation paradigm that uses surface electromyography (sEMG) biofeedback to retrain lower-limb muscle activation patterns. The intervention is designed to reduce abnormal coactivation of agonist-antagonist muscle pairs and facilitate more efficient torque generation during functional movements. sEMG electrodes will be placed bilaterally over the tibialis anterior, gastrocnemius, and quadriceps muscles. EMG signals will be acquired in real time, processed, and used to control on-screen tasks within a custom Unity-based software environment. Participants will engage in interactive tasks where selective activation of target muscles allows them to move a virtual avatar, align a gauge, or achieve movement goals while minimizing antagonist activity. Each MINT session will last approximately 60 minutes and will be delivered immediately following AIH or sham exposure. Sessions will include calibration of EMG channels, a brief familiarization period, and four to five tra

Eligibility

Sex: ALLMin age: 18 YearsMax age: 75 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Diagnosis of clinically definite multiple sclerosis * Patient-Determined Disease Steps (PDDS) score between 3 and 6 * Relapse-free for at least 6 months prior to enrollment * Age ≥ 18 years and ≤ 75 years * Resting oxygen saturation (SpO₂) ≥ 95% on room air * Systolic blood pressure between 85-140 mmHg and diastolic blood pressure between 55-90 mmHg * Modified Ashworth Scale (MAS) score ≤ 3 at the ankle and knee * Mini-Mental State Examination (MMSE) score ≥ 24 * Ability to walk at least 10 meters with or without an assistive device * Ability to perform active ankle dorsiflexion and plantarflexion Exclusion Criteria: * Uncontrolled hypertension or hypotension outside the required ranges * History of epilepsy or seizures * Uncontrolled pulmonary, cardiovascular, or orthopedic disease * Premorbid or ongoing major psychiatric illness (e.g., major depression, psychosis) * Other neurological disease (e.g., stroke, traumatic brain injury, peripheral neuropathy) * Illnesses with potential to cause brain injury * Frequent or severe unexplained headaches * Pregnancy * Implanted medical devices (e.g., pacemakers, intrathecal pumps, brain stimulators)

Outcomes

Primary Outcomes

Six-Minute Walk Test (6MWT)

Participants walk as far as they safely can in six minutes along a marked course, and total distance (meters) is recorded.

Time frame: Change in distance (meters) from pre-training assessment (Day 1, before the first intervention) to Immediate Post (Day 5, after the final intervention), 1-week follow-up (Day 14-21), and 1-month follow-up (Day 36-41).

Secondary Outcomes

Ten-Meter Walk Test (10MWT)

Measures gait speed over 10 meters at a self-selected comfortable pace, averaged across two trials.

Time frame: Baseline/pre-training (Day 1) to immediately post-intervention (Day 5), with retention assessed at the 1-week (Day 14 to 21) and 1-month (Day 36 to 41)

Stair Climb Test (SCT)

Assesses functional mobility and lower-limb power. Participants ascend a standardized 12-step staircase (17 cm per step, 2.04 m total) as quickly and safely as possible across three trials, with ascent time recorded and handrail use documented.

Time frame: Baseline/pre-training (Day 1) to immediately post-intervention (Day 5), then 1-week (Day 14 to 21) and 1-month (Day 36 to 41) follow-ups

Maximal Voluntary Contraction (MVC) Testing

Measures maximal strength of the trained leg on a Biodex dynamometer across ankle plantarflexion, dorsiflexion, knee flexion, and knee extension. Participants perform 3 to 5 maximal isometric contractions (10 seconds each) per movement while surface EMG quantifies agonist activation and antagonist coactivation.

Time frame: Baseline/pre-training (Day 1) to immediately post-intervention (Day 5), then 1-week (Day 14 to 21) and 1-month (Day 36 to 41) follow-ups

Fatigability Testing

Quantifies muscle fatigue as the percent decline in torque across 20 consecutive maximal isometric plantarflexion contractions (5 to 10 seconds each) on the Biodex, with surface EMG monitoring changes in activation and coactivation through the series.

Time frame: Baseline/pre-training (Day 1) to immediately post-intervention (Day 5), then 1-week (Day 14 to 21) and 1-month (Day 36 to 41) follow-ups

Ankle Proprioception Testing

Assesses joint sense on the trained leg via the Biodex while the participant is blindfolded with noise-cancelling headphones. It includes a movement detection threshold (trigger press when slow passive rotation is first felt, 5 to 6 trials) and joint position matching (reproducing a passively set target angle, 6 to 8 trials), with surface EMG confirming no compensatory activity.

Time frame: aseline/pre-training (Day 1) to immediately post-intervention (Day 5), then 1-week (Day 14 to 21) and 1-month (Day 36 to 41) follow-ups

Acute Intermittent Hypoxia Combined With Gait Training in Multiple Sclerosis

Overview

Conditions

Interventions

Eligibility

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts