[1] Leiden Univ, Med Ctr, Dept Neurol, NL-2300 RC Leiden, Netherlands
[2] Univ Penn, Dept Neurol, Philadelphia, PA 19104 USA
[3] Univ Hosp La Fe, Dept Neurol, Valencia, Spain
[4] Stanford Univ, Ctr Narcolepsy, Dept Psychiat & Behav Sci, Palo Alto, CA 94304 USA