Elizabeth W Loder1,2,3, Brian McGeeney4,5,6. 1. Department of Neurology, Brigham and Women's Hospital, Boston, MA, USA. eloder@bwh.harvard.edu. 2. Harvard Medical School, Boston, MA, USA. eloder@bwh.harvard.edu. 3. Graham Headache Center, Brigham and Women's Faulkner Hospital, Boston, MA, USA. eloder@bwh.harvard.edu. 4. Department of Neurology, Brigham and Women's Hospital, Boston, MA, USA. 5. Harvard Medical School, Boston, MA, USA. 6. Graham Headache Center, Brigham and Women's Faulkner Hospital, Boston, MA, USA.