[1] Schlosspk Klin, Dept Neurol, Berlin, Germany
[2] Univ Copenhagen, Dept Neurol, Copenhagen, Denmark
[3] Univ Copenhagen, Danish Headache Ctr, Copenhagen, Denmark
[4] Univ Pittsburgh, Dept Otolaryngol, Pittsburgh, PA 15260 USA
[5] Univ Pittsburgh, Dept Neurol, Pittsburgh, PA 15260 USA
[6] Alfred Hosp, Monash Univ Dept Med, Melbourne, Vic, Australia
[7] Alfred Hosp, Dept Neurol, Melbourne, Vic, Australia
[8] Charing Cross Hosp, Dept Clin Neurosci, London, England
[9] Johns Hopkins Univ, Sch Med, Dept Otolaryngol Head & Neck Surg, Baltimore, MD 21205 USA
[10] Ctr Hosp Emile Mayrisch, Dept Neurol, Esch Sur Alzette, Luxembourg
[11] Univ Pavia, Dept Neurol Sci, HSC & BCC Natl Neurol Inst IRCCS C Mondino Fdn, I-27100 Pavia, Lombardy, Italy
[12] Univ Munster, Dept Neurol, D-4400 Munster, Germany
[13] Johns Hopkins Univ, Sch Med, Dept Neurol, Baltimore, MD 21205 USA