[1] Glaxo SmithKline SA, Dept Med, Area Terapeut Neurociencias, Madrid 28760, Spain
[2] Hosp Doce Octubre, Serv Neurol, Madrid, Spain
[3] Univ Autonoma Madrid, Fac Med, Hosp Univ La Paz, Serv Farmacol Clin, Madrid, Spain
[4] Univ Complutense, Fac Med, Dept Prevent Med, E-28040 Madrid, Spain