[1] NINCDS, NIH, Bethesda, MD 20892 USA
[2] George Washington Univ, Sch Publ Hlth & Hlth Serv, Dept Epidemiol & Biostat, Washington, DC USA
[3] Univ Penn, Dept Neurol, Philadelphia, PA 19104 USA
[4] Emory Univ, Sch Med, Dept Pharmacol, Atlanta, GA 30322 USA
[5] Harvard Univ, Sch Med, Boston, MA USA
[6] Columbia Presbyterian Med Ctr, Coll Phys & Surg, New York, NY 10032 USA
[7] Baylor Coll Med, Dept Neurol, Houston, TX 77030 USA
[8] Yale Univ, Sch Med, Dept Neurol, New Haven, CT 06510 USA