[1] Harvard Univ, Sch Med, Boston Childrens Hosp, Ctr Pain & Brain, Waltham, MA USA
[2] Harvard Univ, Sch Med, Massachusetts Gen Hosp, Waltham, MA USA
[3] Uppsala Univ, Dept Psychol, Uppsala, Sweden
[4] Harvard Univ, Sch Med, Boston Childrens Hosp, Chron Headache Program, Waltham, MA USA