[1] Copenhagen Univ Hosp, Rigshospitalet Glostrup, Danish Headache Ctr, Dept Neurol, Copenhagen, Denmark
[2] Univ Copenhagen, Dept Clin Med, Copenhagen, Denmark
[3] Natl & Kapodistrian Univ Athens, Aeginit Hosp, Dept Neurol 1, Athens, Greece
[4] Univ Copenhagen, Rigshospitalet Glostrup, Dept Neurorehabil Traumat Brain Injury, Copenhagen, Denmark
[5] Teva Netherlands BV, Amsterdam, Netherlands
[6] Univ Bern, Univ Hosp Bern, Inselspital, Dept Neurol, Bern, Switzerland
[7] Lund Univ, Dept Clin Sci Lund, Skaneuro Neurol Clin, Lund, Sweden
[8] Univ Autonoma Barcelona, Vall Hebron Hosp, Headache Unit, Barcelona, Spain
[9] Univ Autonoma Barcelona, Res Inst, Res Grp, Barcelona, Spain
[10] Newcastle Tyne Hosp NHS Fdn Trust, Newcastle, NSW, Australia
[11] Charles Univ Prague, Inst Neuropsychiat Care, Ist Sch Med, Prague, Czech Republic
[12] Oslo Headache Ctr, Private Practice, Oslo, Norway
[13] Univ Lisbon, Centro Estudos Egas Moniz, Fac Med, Lisbon, Portugal
[14] Univ Tampere, Fac Med & Hlth Technol, Tampere, Finland
[15] Teva Branded Pharmaceut Prod R&D Inc, W Chester, PA USA
[16] Univ Pavia, Dept Brain & Behav Sci, Pavia, Italy
[17] IRCCS Mondino Fdn, Pavia, Italy