1. Headache Section, Center for Neurologic Restoration, Neurological Institute Cleveland Clinic Cleveland Ohio USA
2. Center for Outcomes Research and Evaluation, Neurological Institute Cleveland Clinic Cleveland Ohio USA
3. Department of Quantitative Health Sciences, Lerner Research Institute Cleveland Clinic Cleveland Ohio USA
4. Teva Pharmaceuticals Parsippany New Jersey USA
5. Teva Branded Pharmaceutical Products R&D, Inc. West Chester Pennsylvania USA
6. Center for Population Health Research Cleveland Clinic Cleveland Ohio USA