Fig. 1
From: Field testing of the ICHD-3β and expert opinion criteria for chronic migraine
Flow chart of the study. CTTH: chronic tension-type headache; NDPH: new daily persistent headache; Headache NOS: headache not otherwise specified; CM: chronic migraine ; CM- : chronic migraine without medication overuse; CM+: chronic migraine with medication overuse; ICHD-3β: International Classification of Headache Disorders,3rd edition beta version; EO: Expert Opinion criteria; MOH: medication overuse headache