[1] Schlosspk Klin, Dept Neurol, D-14059 Berlin, Germany
[2] Univ Copenhagen, Danish Headache Ctr, DK-2600 Copenhagen, Denmark
[3] Univ Copenhagen, Dept Neurol, DK-2600 Copenhagen, Denmark
[4] Univ Pittsburgh, Dept Otolaryngol, Pittsburgh, PA 15260 USA
[5] Univ Pittsburgh, Dept Neurol, Pittsburgh, PA 15260 USA
[6] Dept Neurol, Melbourne, Vic 3004, Australia
[7] Monash Univ, Dept Med, Alfred Hosp, Melbourne, Vic 3004, Australia
[8] Charing Cross Hosp, Dept Clin neurosci, London W6 8RF, England
[9] Johns Hopkins Univ, Dept Otolaryngol Head & Neck Surg, Sch Med, Baltimore, MD 21205 USA
[10] Ctr Hosp Emile Mayrisch, Dept Neurol, L-4240 Esch Sur Alzette, Luxembourg
[11] Univ Pavia, Dept Neurol Sci, HSC & BCC Natl Neurol Inst IRCCS Cn Mondino Fdn, IT-27100 Pavia, Lomabardy, Italy
[12] Univ Munster, Dept Neurol, D-48149 Munster, Germany
[13] Johns Hopkins Univ, Sch Med, Dept Neurol, Baltimore, MD 21205 USA