ICHD classification and diagnosis of migraine are further subdivided. Overall ICHD-3 beta distinguishes 29 migraine subtypes. The following table outlines the main subtypes and their ICHD-1, -2, -3 beta and ICD-10 codes. Migraine without aura also referred to as a "common migraine", (previously known as "hemicrania simplex") is a specific neurological disorder characterized by recurrent, throbbing headaches that often affect one side of the head (i.e., it is unilateral), are of at least moderate intensity, and may cause nausea, phonophobia or photophobia. One defining characteristic of the common migraine is a lack of the visual disturbances known as an aura. The exact International Classification of Headache
Chronic paroxysmal hemicrania and are found in 1 in 1000 people. Cluster headaches occur primarily in men, while CPH is more commonly diagnosed in women. The female to male ratio of diagnosed patients can range anywhere from 1.6:1 to 2.36:1. Symptoms may begin to appear at any age, but onset usually occurs in adulthood with a mean starting age within the thirties. CPH was discovered by Norwegians Ottar Sjaastad and Inge Dale in 1974. The term 'chronic paroxysmal hemicrania' was first used in 1976 by Sjaastad to describe a condition seen in two of their patients who were experiencing repeated solitary and limited