Inclusion Criteria:  Clinical diagnosis: RRMS (relapsing-remitting MS) Prescribed Tysabri (Natalizumab) by their physician Natalizumab/Tysabri-naïve Ages 18-60 Access to a smartphone  Exclusion Criteria:  Inability to perform 5 or more of the BeCare App tasks independently EDSS >6.5 Corrective Visual Acuity lower than 20/200 Any chronic illness that has not been stable for at least six months (medication changes during the past year for that condition are not exclusionary) Malignancy/previous chemotherapy treatment for neoplastic disease Untreated or unstable major depression or bipolar disease Clinical diagnosis: SPMS (Secondary-progressive multiple sclerosis) or PPMS (primary-progressive MS) Patients previously treated with Tysabri