[1] Bangkok Hosp, Bangkok Hosp Grp, Neurosci Ctr, Comprehens Headache Clin, Bangkapi, Huay Khwang, Thailand
[2] Bangkok Hosp, Bangkok Hosp Grp, Bangkok Eye Ctr, Bangkapi, Huay Khwang, Thailand
[3] Thomas Jefferson Univ, Jefferson Headache Ctr, Philadelphia, PA USA
[4] Mayo Clin, Dept Neurol, Rochester, MN USA