The Concept of Basilar Artery Migraine

It was 1961 when Bickerstaff first wrote about and drew attention to Basilar Artery Migraine. He was the first to ever introduce the concept, and he described symptoms that included bilateral disturbance of vision, ataxia, dysarthria, vertigo, tinnitus, and face and/or limb paresthesias. These symptoms, as Bickerstaff described, were followed by severe throbbing headache, usually in the occipital region (near the base of the skull, in the back of the head).

The visual symptoms that Bickerstaff described sudden, bilateral visual loss that occurred over a period of seconds and persisted for up to 15 minutes, and vivid flashes of light that occurred throughout the patients' visual field.

Bickerstaff described Basilar Artery Migraine as having symptoms that lasted between 2 and 45 minutes. He went on to say that the symptoms rapidly disappeared after this time, but that if the patient had suffered complete loss of vision, that particular symptom tended to disappear less quickly. The patients' vision normally progressed through a phase of "graying vision" before full vision returned.

None of the patients described in this study had the characteristic "fortification spectra" of classic migraine in addition to their symptoms of brainstem ischemia.

Majority of Bickerstaff's Study Patients Adolescent Girls

Twenty-six of the 34 patients that Bickerstaff studied and described in his 1961 article were adolescent girls. Most of the attacks suffered by these patients were infrequent. In the adolescent girls, attacks appeared to be associated with the menstrual cycle.

Bickerstaff also wrote that episodes of Basilar Artery Migraine normally subsided over a period of years, and that they are often replaced by other types of migraine--more common varieties such as classical or common migraine.

Impossible to Prove a Definite Diagnosis

It was impossible, according to Bickerstaff, to prove a definite diagnosis. However, he stated that considerations such as (1) occurrence of other, more "typical" migrainous attacks in the studied patients, (2) absence of all neurologic abnormality in patients between attacks, (3) the particular mode of onset, (4) the headache normally associated with Basilar Artery Migraine, and (4) the incidence of family history of some form of migraine made the diagnosis of Basilar Artery Migraine most likely.

Impaired Consciousness and Brainstem Ischemia

In a later study, Bickerstaff described another group of patients with Basilar Artery Migraine. This group suffered symptoms of impaired consciousness during their BAM attacks. Bickerstaff proposed that this was caused by "transient ischemia of the reticular activating system of the brainstem secondary to vasomotor disturbance in the distribution of the basilar artery."

Bickerstaff also later suggested the two causes that could lead to loss of consciousness in patients with migraine: brainstem ischemia of the reticular activating system and ischemia producing seizure in a potentially epileptic brain. The second of these is much less common. The first, the brainstem ischemia, is what we see in an attack of Basilar Artery Migraine.