If you've heard of this form of Migraine before, you've probably heard or seen the term Basilar Artery Migraine (BAM). Under the International Headache Society's International Classification of Headache Disorders, 2nd Edition, the newer name for this form of Migraine is Basilar-Type Migraine (BTM). It has also been called Bickerstaff syndrome, brainstem Migraine, and vertebrobasilar Migraine. The term Basilar-Type Migraine is actually a bit misleading as it implies that the Migraine attack is vascular in origin. It was actually termed Basilar because it was first believed to be a result of spasm of the basilar artery and the subsequent ischemia. Since the time when the term Basilar came into use, however, it has been shown that Migraine is a genetic neurological disease, and BTM, as other types of Migraine are neural in origin. As with all Migraine, there is a vascular component once the Migraine begins, but the origin is neurological. Early literature on the subject suggested that BTM was most common in adolescent females. However, continued research and statistical analysis has shown BTM to affect all age groups and both male and female. BTM does exhibit the same female predominance seen overall in Migraine; there are three times as many female sufferers as male.
A Basilar-Type Migraine is a Migraine that has aura symptoms originating from the brainstem and/or affecting both hemispheres of the brain at the same time, but with no motor weakness. The aura of BTM usually lasts less than 60 minutes, but in some cases can be more extended. Many Migraineurs who have BTM also report Migraine with typical aura. The aura of Basilar-Type Migraine can include temporary blindness, which is one reason they can be quite terrifying. However, BTM is actually essentially Migraine with aura with the aura localized to the brainstem. Still, because of that localization, Migraine-specific medications such as the triptans and ergotamines are contraindicated for BTM. Of the preventive medications, it's recommended that beta blockers be avoided in cases of BTM. Because of the medication contraindications, I highly recommend that Migraineurs who experience BTM wear some kind of medical identification at all times. Diagnosis of Basilar-Type Migraine requires at least two attacks meeting the following criteria:
- Aura consisting of at least two of the following fully reversible symptoms, but no motor weakness:
- dysarthria (impairments or clumsiness in the speaking of words due to diseases that affect the oral, lingual, or pharyngeal muscles)
- vertigo (sense of spinning)
- tinnitus
- hypacusia (impaired hearing)
- diplopia (double vision)
- visual symptoms simultaneously in both temporal and nasal fields of both eyes
- ataxia (incoordination and unsteadiness)
- decreased level of consciousness
- simultaneously bilateral paresthesias (abnormal or unpleasant sensation often described as numbness or as a prickly, stinging, or burning feeling)
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