[1] Univ Utrecht, Univ Med Ctr Utrecht, Julius Ctr Hlth Sci & Primary Care, POB 85500,Stratenum 6-131, NL-3508 GA Utrecht, Netherlands
[2] Univ Utrecht, Dept Neurol, Univ Med Ctr Utrecht, Utrecht, Netherlands
[3] Ural State Med Univ, Dept Neurol, Ekaterinburg, Russia
[4] Int Headache CenterEurope Asia, Ekaterinburg, Russia
[5] Radboud Univ Nijmegen, Dept Neurol, Med Ctr, Nijmegen, Netherlands
[6] Univ Amsterdam, Dept Neurol, Amsterdam UMC, Amsterdam, Netherlands
[7] Univ Copenhagen, Rigshospitalet Glostrup, Danish Headache Ctr, Dept Neurol, Copenhagen, Denmark
[8] Saltro Diagnost Ctr Primary Care, Utrecht, Netherlands