[1] Univ Fed Rio Grande do Sul, Div Neurol, Hosp Clin Porto Alegre, BR-90035903 Porto Alegre, RS, Brazil
[2] Univ Fed Rio Grande do Sul, Med Sci Postgrad Program, BR-90035903 Porto Alegre, RS, Brazil
[3] Univ Fed Sao Carlos, Dept Med, Sch Med, BR-13560 Sao Carlos, SP, Brazil
[4] Merck Res Labs, Sci Affairs Neurol & Psychiat, Upper Gwynedd, PA USA
[5] Albert Einstein Coll Med, Dept Neurol, New York, NY USA