Long-Term Outcomes and Clinical Characteristics of Hypnic Headache Syndrome: 40 Patients Series From a Tertiary Referral Center

Objective Hypnic headaches (HHs) are unique because of late life onset and characteristic periodic nocturnal awakening. We retrospectively identified 40 cases at a tertiary headache referral center over the course of 6 years and assessed response to conventional treatments. Methods This was a retrospective study in which patients were identified using primary and secondary ICD‐9 diagnostic codes of HHs (339.81) from October 2008 until December 2014 using the International Classification of Headache Disorders II and III‐beta criteria for diagnosis. Baseline characteristics were collected. Primary outcome was response to medications divided into 4 categories: complete response (headaches completely gone), moderate response (≥50% decrease in frequency), partial response (