[1] Univ Copenhagen, Glostrup Hosp, Danish Headache Ctr, Dept Neurol, DK-2600 Copenhagen, Denmark
[2] Univ Copenhagen, Rigshosp, Dept Clin Neurophysiol, Dept Neurol, DK-2100 Copenhagen, Denmark
[3] Aarhus Univ Hosp, Headache Clin, DK-8000 Aarhus, Denmark
[4] Aarhus Univ Hosp, Danish Pain Res Ctr, DK-8000 Aarhus, Denmark
[5] Bispebjerg Hosp, Univ Copenhagen Hosp, Dept Neurol, DK-2400 Copenhagen, Denmark
[6] Univ Copenhagen, Rigshosp, Juliane Marie Ctr, Dept Neuropediat, DK-2100 Copenhagen, Denmark
[7] Univ Southern Denmark, Res Unit Gen Practice, DK-5000 Odense, Denmark
[8] SVS, Dept Neurol, Esbjerg, Denmark