1. Headache Science Centre, C. Mondino National Institute of Neurology Foundation, IRCCS, Pavia, Italy
2. Department of Neurology, University Hospital Basel, Switzerland
3. Department of Radiology and Nuclear Medicine, Division of Neuroradiology, University Hospital Basel, Switzerland
4. Department of Neurology, Technische Universitaet Muenchen, Germany
5. Headache Group – Department of Neurology, University of California, USA