Non-invasive Electrical Spinal Cord Stimulation To Restore Upper Extremity Function in Multiple Sclerosis

Inclusion Criteria: 1. Diagnosis of MS 2. Age between 21 and 70 3. Presence of upper extremity functional impairment (correlating with raw score ≤34 on NeuroQOL Upper Extremity Function short-form questionnaire), 4. Ability to attend intervention and assessment sessions 3 times per week. 5. For women of childbearing potential, willingness to provide confirmation of a negative over-the-counter home pregnancy test within 2 weeks of study entry and prior to each intervention arm. Exclusion Criteria: 1. Relapse within the past 6 months (given that natural recovery from relapse could skew results) 2. Active implanted stimulator or baclofen pump 3. Upper extremity botox injection within the past 6 months 4. Unstable dalfampridine usage during study duration (which may interfere with functional outcomes) 5. Coexisting neurological condition that could interfere with interpretation of testing results (hx of stroke, traumatic brain injury, epilepsy/seizure, ALS, spinal cord injury, central nervous system vasculitis, intracranial tumor, intracranial aneurysm, cervical myelopathy/radiculopathy or peripheral neuropathy (diabetic polyneuropathy, entrapment neuropathy), etc.) 6. History of major active psychiatric illness that could interfere with treatment, such as severe depression, alcohol/drug abuse, or dementia 7. Serious comorbidities (e.g., cardiac arrhythmia, uncontrolled hypertension, respiratory disease, cancer, renal failure, chronic infectious disease, rheumatic disease, frequent UTIs, etc.) that would prevent participation in study activities 8. Presence of severe joint contractures in the affected hand and arm that may interfere with study activities or outcome measures 9. Severe spasticity, as defined by an Ashworth score of 4 in both sides of the upper limb 10. Pregnant and/or breastfeeding 11. Lack of ability to fully comprehend, cooperate, and/or safely perform study procedures in the investigator's opinion/judgment 12. Inability to give consent