[1] Primary Care Network Inc, Headache Care Ctr, Springfield, MO 65807 USA
[2] Mayo Clin, Coll Med, Dept Neurol, Scottsdale, AZ USA
[3] Cleveland Nasal Sinus & Sleep Ctr, Cleveland, OH USA
[4] NYU, N Shore Univ Hosp, Sch Med, Manhasset, NY USA
[5] Neurol Associates Tulsa, Tulsa, OK USA
[6] Univ Texas, SW Med Sch, Dallas, TX 75230 USA
[7] Univ Minnesota, Minneapolis, MN USA
[8] SW Missouri State Univ, Dept Biol, Springfield, MO 65802 USA