BAM is a variant on the theme of migraine. It is a rare form of
migraine, accounting for somewhere between 1 in 400 and 1 in 500
of all clinically diagnosed migraine cases.
When classifying headaches according to presumed site of origin,
BAM belongs in the category of "episodic headaches of uncertain
mechanism." This grouping includes (1) migraine, (2) cluster
headache, and (3) acute cerebral vascular insufficiency.
