1. Department of NeurologyJefferson Headache CenterPhiladelphia PA USA
2. Department of Neurology and Neuro-OncologyDent Neurologic Headache CenterAmherst NY USA
3. California Medical Clinic for HeadacheSanta Monica CA USA
4. Carolina Headache InstituteDurham NC USA
5. North American Science Associates IncMinneapolis MN USA
6. Michigan Head Pain and Neurological InstituteAnn Arbor MI USA
7. Department of Scientific, Medical and Governmental Affairs, electroCoreLLCBasking Ridge NJ USA
8. Dalessio Headache Center at Scripps ClinicLa Jolla CA USA
9. Department of NeurologyGeisel School of Medicine at DartmouthHanover NH USA
10. Dr. Tepper was at Cleveland Clinic Headache CenterCleveland, OH, at the time of study completion.