Fig.1.

Study design. Thirty-one patients were enrolled in VALIANT, a double-blind, crossover design study. Subjects were randomized to two groups, Group 1(VPA/placebo) or Group 2 (Placebo/VPA), following a screening visit that occurred at visit 1. Group 1 (13 subjects) was placed on VPA at visit 2 (V2). 6 months later, Group 1 subjects discontinued VPA and began to take placebo at visit 4 (V4). Group 1 subjects continued to take placebo for an additional 6 months until study visit 6 (V6). Group 2 (18 subjects) was given placebo at V2 for 6 months when they discontinued placebo and began taking VPA at V4. Group 2 subjects continued VPA for 6 months until V6.