[1] HOP LA PITIE SALPETRIERE,INSERM,UNITE 360,F-75651 PARIS 13,FRANCE
[2] ERASMUS UNIV ROTTERDAM,SCH MED,DEPT EPIDEMIOL & BIOSTAT,NL-3000 DR ROTTERDAM,NETHERLANDS
[3] UNIV ROTTERDAM HOSP,DEPT NEUROL,ROTTERDAM,NETHERLANDS
[4] UNIV BORDEAUX 2,PELLEGRIN HOSP,DEPT NEUROL,F-33076 BORDEAUX,FRANCE
[5] UNIV BORDEAUX 2,INSERM,UNITE 360,F-33076 BORDEAUX,FRANCE
[6] UNIV FLORENCE,DEPT NEUROL,FLORENCE,ITALY
[7] SANTA CATARINA HOSP,DEPT NEUROL,GIRONA,SPAIN
[8] UNIV NAVARRA,DEPT NEUROL,E-31080 PAMPLONA,SPAIN
[9] MAYO CLIN & MAYO FDN,DEPT HLTH SCI RES,ROCHESTER,MN 55905