1. Department of Neurology; NYU Langone Medical Center; New York University School of Medicine; New York, NY, USA
2. Danish Headache Center and Department of Neurology; University of Copenhagen, Rigshospitalet Glostrup; Glostrup Denmark
3. Department of Neurology; Albert Einstein College of Medicine; Bronx NY, USA
4. Department of Epidemiology and Population Health; Albert Einstein College of Medicine; Bronx NY, USA
5. Montefiore Headache Center; Bronx NY, USA
6. Unit for Quality and Patient Safety; Capital Region of Denmark; Copenhagen Denmark