1. University of Applied Sciences Hof , Institute of Information Systems , Alfons-Goppel-Platz 1 , 95028 Hof , Germany
2. Migraine and Headache Clinic Königstein , Ölmühlweg 31 , 61462 Königstein im Taunus , Germany
3. Institute of Medical Psychology and Medical Sociology, center of nervous diseases , University of Rostock , Gehlsheimer Straße 20 , 18147 Rostock , Germany