PTH and Headache: We expanded the headache onset criterion to 3 months after head injury (per ICHD-3 A5.2.2.1),67 and our research group recently found no phenotypic difference between veterans with headache onset within 7 days (ICHD-3 5.2.2) vs 8 to 90 days (A5.2.2.1) after head injury.67 Thus, the present sample reasonably reflects veterans with persistent PTH, including those misdiagnosed owing to headache onset greater than 7 days.