[1] Pk Klin Weissensee, Dept Neurol, Berlin, Germany
[2] Univ Calif Los Angeles, David Geffen Sch Med, Los Angeles, CA 90095 USA
[3] Ctr Hosp Emile Mayrisch, Esch Sur Alzette, Luxembourg
[4] Univ Munich, Inst Clin Neurosci, Munich, Germany
[5] Univ London Imperial Coll Sci Technol & Med, Neurootol Unit, Ctr Neurosci, London, England
[6] Univ Pittsburgh, Sch Med, Inst Eye & Ear, Pittsburgh, PA USA
[7] Univ Calif San Francisco, UCSF Headache Grp, San Francisco, CA 94143 USA
[8] Robert Koch Inst, D-1000 Berlin, Germany
[9] Charite, Dept Neurol, Berlin, Germany
[10] Univ Pavia, Dept Neurol Sci, I-27100 Pavia, Italy
[11] Univ Pavia, Headache Sci Ctr, Natl Inst Neurol C Mondino Fdn, I-27100 Pavia, Italy