The goal of this observational study is to validate a novel, cost-effective method for real-world assessment using patient-acquired selfie videos in people with multiple sclerosis. The investigators aim to prove the feasibility and validity of monitoring walking changes remotely through a truly patient-centered, low-burden, low-cost approach. The main question this study aims to answer is: do remotely collected walking and speech videos from a mobile phone match the information investigators can gather from an in person visit? Participants will collect 5 selfie videos at baseline, 3 months, 6 months and 12 months (about 15 minutes every 3 months). They will also come in person at baseline, 6 months, and 12 months for in person data collection (about 1 hour per in person visit).