In Bille's large study, 35% to 50% of the children became asymptomatic after 4 years to 6 years of observation (Bille 1962). When Bille re-evaluated his cohort near the age of 50 years, more than half of the subgroup that had “pronounced” migraine at about 6 years still had migraine at the age of 50. However, one fourth of the subgroup stopped having migraine by the age of 25 years (Bille 1997). Among children who attended a neurologic clinic in 1983 because of headaches, about 80% were much improved 10 years later (Dooley and Bagnell 1995). Migraine complicated by prolonged neurologic signs has rarely been associated with a permanent neurologic deficit, and some of these cases may have been due to unrecognized metabolic diseases. Severe unilateral headaches with neurologic signs (SMART syndrome) may occur in children years after treatment for brain tumors as sequelae of cranial radiation and chemotherapy (Armstrong et al 2014). Vomiting after mild head injury seems more common in children with migraine headache (Jan et al 1997). Among women aged 15 to 45 years, especially those who smoked or took oral contraceptives, there was a significant association between migraine and stroke (Lidegaard 1995). Similar studies have not been performed for those under the age of 15 years.