![]() ![]() More research is needed to better understand aura in relation to other phases of the migraine attack, particularly the prodrome that is initiated in other parts of the brain. Whether CSD triggers migraine attacks, is a result of the true inciting mechanism, or happens independently remains unknown. ![]() Auras may also occur without migraine headache. Most people with migraine do not experience aura, and those who do may not experience aura in all their attacks. These differences suggest different aura semiologies may originate in different parts of the brain. 6 Notably, individuals with nonvisual aura have higher resting state fMRI differences in the left lingual gyrus (within the visual network) and the right anterior insula (within the sensorimotor network) compared with people who have migraine with simple visual aura or without aura. 8 Perfusion changes on fMRI start in the occipital cortex and spread anteriorly with progression of visual aura. Hypoperfusion that occurs with aura does not reach the level of ischemic changes.ĬSD has been seen on advanced neuroimaging (ie, functional MRI ) in those with visual aura as functional connectivity differences in the extrastriatal cortex. CSD also explains why aura symptoms occur progressively with slow spread before resolving, whereas vascular symptoms are immediate and sometimes irreversible. ![]() Because these changes are due to electrophysiologic changes rather than decreased blood flow, aura symptoms are reversible. 3 Thus, blood vessel changes result from CSD and not the direct cause of aura. 6,7 These changes are due to electrolyte and neurotransmitter fluctuations that propagate from the nerve to adjacent cells. 5 The wave of CSD causes physiologic changes of hyperemia followed by a prolonged phase of oligemia. The aura phase of a migraine attack is thought to be due to cortical spreading depression (CSD), which is a slowly propagating wave of depolarization followed by cortical inhibition for up to 30 minutes and then depression of or decrease in electrical activity. This review discusses the different types of nonvisual aura associated with migraine. Better understanding of different types of migraine aura will help providers appropriately diagnose migraine aura, and better understanding of the pathophysiology will allow providers to give safe and effective treatment as well as education to people who experience what can be frightening symptoms. Considering aura variability among people with migraine and even between migraine attacks in an individual with migraine, there is a focus on how auras are influenced by migraine pathophysiology and how they could be managed. Nonvisual auras comprise sensory, motor, and language symptoms. The most common type of aura is visual (see Migraine Visual Aura & Other Visual Phenomena in this issue) however, other types of aura symptoms can be seen with migraine instead of or in addition to visual aura. 4 No specific gene associated with migraine with aura has been identified, except in familial hemiplegic migraine, a largely monogenic disorder. Those with first-degree relatives who have migraine with aura have a higher risk of developing the disease compared with those whose first-degree relatives have migraine without aura. ![]()
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