[1] Univ Copenhagen, Fac Hlth & Med Sci, Rigshosp Glostrup, Neurol, Copenhagen, Denmark
[2] Univ Copenhagen, Fac Hlth & Med Sci, Rigshosp Glostrup, Int Headache Soc, Copenhagen, Denmark
[3] Univ Copenhagen, Fac Hlth & Med Sci, Rigshosp Glostrup, Danish Headache Ctr, Copenhagen, Denmark
[4] Univ Copenhagen, Fac Hlth & Med Sci, Rigshosp Glostrup, Dept Neurol, Copenhagen, Denmark