Motor Evoked Potentials as a Biomarker in Alemtuzumab Treated Multiple Sclerosis Patients

Study Design: Phase 4, pilot, single center, observational study. MEP\'s will be obtained twice, two weeks apart at baseline and every 6 months for 36 months (total of 14 sessions of MEP\'s) MEP\'s will include: 1. Onset latencies and CMCT to bilateral abductor pollicis brevis and tibialis anterior muscles 2. MEP amplitudes and the ratio of the central to peripherally obtained motor amplitudes (MEP-M ratio) to bilateral abductor pollicis brevis and tibialis anterior muscles Clinical measures (EDSS, MEP\'s, T25FWT, 6MWT, 9HPT) will be obtained at baseline and every 6 months for 36 months. Study location: Single center in Canada Study Objectives: Primary: To evaluate the reliability of MEP\'s in Alemtuzumab treated MS patients over a 36 month period. Secondary: To determine the degree of correlation between MEP\'s and presently used clinical measures of efficacy (EDSS, 6MWT, T25FWT, 9HPT) and to determine if MEP\'s can predict who will require a third cycle of Alemtuzumab.