[1] Rigshosp Glostrup, Copenhagen Univ Hosp, Danish Headache Ctr, Dept Neurol, Glostrup, Denmark
[2] Friedrich Alexander Univ Erlangen Nurnberg, Inst Physiol & Pathophysiol, Erlangen, Germany
[3] Univ Copenhagen, Dept Clin Physiol & Nucl Med, Hvidovre, Denmark
[4] Univ Copenhagen, Dept Clin Med, Copenhagen, Denmark
[5] Univ Copenhagen, Dept Clin Biochem, Rigshosp Glostrup, Copenhagen, Denmark