ABSTRACT
The premise of the vasogenic theory is that focal ischemia is the root cause of the migraine aura. Auras are due to hypoperfusion secondary to vasoconstriction of the blood vessel that supplies the cortical lobe corresponding to the aura symptom, be it visual, sensory or motor. Reactive vasodilation would explain the genesis of pain through stimulation of the perivascular pain-sensitive fibers. This theory would be in agreement with the throbbing quality of pain, its varied location and the pain relief caused by vasoconstrictive agents such as ergotamine. Patients undergoing the aura phase of their attacks were studied using 133Xe blood flow techniques and these studies revealed a 17-35% reduction in cerebral blood flow in the posterior regions of the brain. More recent positron emission tomographic scan studies during the aura phase of migraine confirm these results and reveal slowly spreading hypoperfusion. Neither study showed evidence of ischemia.
