 The trial consisted of a 4-week Titration Phase, an 8-week Maintenance Phase, a 1-week Taper Phase, and a 2-week Safety Follow-Up Phase. If subjects met the eligibility criteria, they were randomized to receive either lacosamide 400mgday or placebo during the Maintenance Phase. Subjects assigned to lacosamide were titrated from 100mgday to 400mgday at weekly intervals of 100mg. All subjects who completed the 4-week Titration Phase entered an 8-week Maintenance Phase. No dose adjustment was allowed during the Maintenance Phase. The Treatment Phase was defined as the combined Titration and Maintenance Phases. 