[1] Johns Hopkins Univ, Sch Med, Dept Neurol, Johns Hopkins Outpatient Ctr, Baltimore, MD 21287 USA
[2] Univ Rochester, Dept Neurol, Rochester, NY USA
[3] Univ Rochester, Dept Biostat, Rochester, NY USA
[4] Med Coll Wisconsin, Dept Neurol, Milwaukee, WI 53226 USA
[5] Teva Pharmaceut Ind Ltd, Netanya, Israel
[6] Univ Penn, Dept Neurol, Philadelphia, PA 19104 USA