Disease Etiology  

The etiology of migraine headache is not completely understood. The vascular theory, proposed in the 1940-1950s, theorized that auras were caused by vasoconstriction and that rebound vasodilation caused the pain of migraine headaches (1). However, this theory has been discounted and replaced by the neurovascular theory. According to the neurovascular theory, migraine is “primarily a neurogenic process with secondary changes in cerebral perfusion” (2). Central to the