82 adolescent or adult patients in whom the diagnosis of basilar artery migraine (BAM) had been made or suspected were reviewed. When rigorous criteria were used, the diagnosis could be confirmed in 49 patients (32 women and 17 men). Seven other patients probably had BAM, but did not totally fulfill the criteria. In 26 cases reevaluation did not confirm the diagnosis.
In the 49 patients with definite BAM the age of onset ranged from 10 to 62 years, 65% of them having their first attack in the second or third decade. 40% had BAM attacks only, while 60% had additionally other types of migraine attacks. A typical pattern of attacks with an “ischemic” aura followed by predominantly occipital headache was found in only 57%. The most frequent “ischemic” symptom was bilateral visual impairment (86%). Symptoms and signs of brain stem dysfunction were vertigo (63%), gait ataxia (63%), bilateral paresthesia (61%), bilateral weakness (57%), and dysarthria (57%). 77% of the cases had disorders of consciousness (mainly syncope, confusion and prolonged amnesia). 4 patients (8%) had epileptic seizures during the migraine attacks. 73% had a family history of migraine and 12% of epilepsy. EEG's were always abnormal during the attacks with predominantly localized or generalized mostly paroxysmal slow wave activity. CT scans were normal except for 2 women with repeated BAM attacks, who were smokers and taking contraceptive drugs, and who during an attack experienced a cerebellar and an occipital lobe infarction respectively. Of the 26 patients in whom the diagnosis of BAM could not be confirmed 13 had other types of migraine, while the remaining cases had temporal lobe epilepsy, intermittent vertebral basilar artery insufficiency, orthostatic hypotension or hysterical attacks.