Acute Intermittent Hypoxia Combined With Gait Training in Multiple Sclerosis

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)