About the Authors

Dagny Holle

dagny.holle@uk-essen.de

Affiliation Department of Neurology, University of Duisburg-Essen, Essen, Germany

Benedict Schulte-Steinberg

Affiliation Department of Neurology, University of Duisburg-Essen, Essen, Germany

Sebastian Wurthmann

Affiliation Department of Neurology, University of Duisburg-Essen, Essen, Germany

Steffen Naegel

Affiliation Department of Neurology, University of Duisburg-Essen, Essen, Germany

Ilya Ayzenberg

Affiliation Department of Neurology, Ruhr University Bochum, Bochum, Germany

Hans-Christoph Diener

Affiliation Department of Neurology, University of Duisburg-Essen, Essen, Germany

Zaza Katsarava

Affiliation Department of Neurology, Evangelical hospital Unna, Unna, Germany

Mark Obermann

Affiliation Department of Neurology, University of Duisburg-Essen, Essen, Germany

Competing Interests

Dagny Holle has received a research grant from Grünenthal, Allergan and the German Ministry of Education and Research (BMBF). Benedict Schulte-Steinberg reports nothing to disclose. Sebastian Wurthmann reports nothing to disclose. Steffen Naegel reports nothing to disclose. Ilya Ayzenberg reports nothing to disclose. Hans-Christoph Diener has received honoraria for participation in clinical trials, contribution to advisory boards or lectures from Addex Pharma, Allergan, Almirall, AstraZeneca, Bayer Vital, Berlin Chemie, Coherex Medical, CoLucid, Böhringer Ingelheim, Bristol-Myers Squibb, GlaxoSmithKline, Grünenthal, Janssen- Cilag, Lilly, La Roche, 3M Medica, Minster, MSD, Novartis, Johnson & Johnson, Pierre Fabre, Pfizer, Schaper and Brümmer, SanofiAventis, and Weber & Weber; received research support from Allergan, Almirall, AstraZeneca, Bayer, Galaxo-Smith-Kline, Janssen-Cilag, and Pfizer. Headache research at the Department of Neurology in Essen is supported by the German Research Council (DFG), the German Ministry of Education and Research (BMBF), and the European Union. Zaza Katsarava: has received research grants and honoraria from Allergan, Bayer, Biogen and Merck, and is an advisory board member for Allergan. Headache research at the Department of Neurology in Essen is supported by the German Research Council (DFG), the German Ministry of Education and Research (BMBF), and the European Union. Mark Obermann: has received scientific grants by the German Federal Ministry of Education and Research BMBF 01EM 0513. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: DH MO HCD. Performed the experiments: DH BSS SW. Analyzed the data: DH SN MO IA. Contributed reagents/materials/analysis tools: ZK IA. Wrote the paper: DH HCD MO SW.