1. Department of Neurology, Danish Headache Center, Copenhagen University Hospital – Rigshospitalet, Copenhagen, Denmark
2. Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
3. Harvard Medical School, Boston, MA, USA
4. Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
5. Danish Headache Knowledge Center, Copenhagen University Hospital – Rigshospitalet, Copenhagen, Denmark
6. Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA