, and presence or absence of aura symptoms. It is suggested that menstrual migraine (90 percent of attacks of MO occur in association with menstruation) may be a specific type of MO. The menstrual migraine is found in 24-25 percent of females with MO. MA is subclassified into migraine with typical aura, migraine with prolonged aura, familial hemiplegic migraine (rare), basilar migraine, migraine aura without headache, and migraine with acute aura onset. Distinctions between cluster headaches and migraines are controversial. Cluster headache is characterized by recurrent, unilateral attacks of great intensity and brief duration; these headaches are accompanied by local signs and symptoms of autonomic dysfunction. Attacks occur in series that last weeks or months (cluster periods). Etiology and pathogenesis are largely unknown, however, differences found between male and female ratios indicate that cluster headache and migraine have a different etiology (12:686, 693). Basilar migraine is a subtype of migraine that is characterized by recurrent headaches, and multiple neurologic symptoms. Vertigo is a common symptom with tinnitus and fluctuating hearing loss (1:616).
Studies with twin pairs are used to investigate genetic and environmental factors; results suggest that both factors may be important in MO and MA. Monozygotic twin pairs have a concordance rate of less than 50 percent; it is higher than that of dizygotic twin pairs. Migraine is reported as transmitted from parents to children; numerous studied report a positive family history of migraine. In a current study, migraineurs did not have a specific personality, marital status, education or employment status, and assortive mating was not likely to explain increased risk of migraine for spouses to probands with MO. Trends towards increased risk among children of probands with MO may be due to increased risk of MO among spouses. Spouses of probands with MA demonstra...