Migraines, once thought benign, may permanently change—even permanently harm—the brain, reveals a multi-study review and meta-analysis.

Migraines associated with either “white matter abnormalities,” or brain volume deficits, may simply alter the brain’s structure. But migraines associated with “silent infarct-like lesions” may harm it.

Indeed, patients experiencing “atypical migraines” may want to seek MRI scans, says Sait Ashina, Headache Program Director of New York’s Beth Israel Medical Center, and co-author of the migraine study appearing in the August 28 Neurology.

Guided by the American Academy of Neurology and US Headache Consortium, Ashina defines “atypical migraines” that may call for MRIs as those including incidents that involve “prolonged aura (including light displays or blind spots) of more than 60 minutes; change in attack frequency, severity, or clinical features; headache onsets after the age of 55 years; presence of neurologic signs or symptoms (double vision, weakness, or difficulty with gait.)”

Sait Ashina, Headache Program Director of New York’s Beth Israel Medical Center

The migraine has traditionally been considered a benign problem lacking long-term consequences. But the recent review, led by University of Copenhagen neurologist Messoud Ashina, found that migraine increased incidences of brain lesions and white matter abnormalities, and altered brain volume. This effect was even greater among those suffering from migraine with auras.

For the meta-analysis, the team reviewed six population-based studies and 13 clinic-based studies to ascertain whether people suffering from migraines, or migraines with aura, had an increased risk of brain lesions, silent abnormalities, or brain volume changes on MRI brains, compared to those without the conditions.

The team found that “migraineurs” with aura possessed a 68 percent increased risk of engendering white matter brain lesions. Migraineurs with no aura saw an increased risk of 34 percent of engendering white matter lesions. The risk for more serious, infarct-like abnormalities increased by 44 percent for those with migraine with aura, compared to those without.

Brain volume changes were more common in those with both migraine and migraine with aura, than in those without.

Migraine is a common neurologic disorder, characterized by what the study calls “paroxysmal attacks of unilateral throbbing headache and autonomic nervous system dysfunction.” About ten to 15 percent of Americans experience migraines, or 36 million people, more than sufferers of diabetes and asthma combined. About one third of those also experience auras.

Sait Mashina notes that white matter abnormalities (WMAs) “are of uncertain clinical significance and are frequent findings on MRI in migraineurs. They are typically described as multiple, small, punctuate lesions in the white matter. Pathologically, they could be related to gliosis (astrocyte proliferation in damaged brain areas), demyelination (loss of myelin covering of nerve fibers), and loss of axons (nerve extensions), which could possibly be due to microvascular damage. However, the causes of these abnormalities remain uncertain.”

Continues Ashina: “The silent infarct-like lessions (ILLs) are described as brain abnormalities on MRI, having a size of at least two to three millimeters. The infarct-like lesions are believed to result from hypoperfusion (ischemia, or blood supply restriction) or microemboli (small blood clots). However, it is possible other mechanisms could also play a role.”

More study is needed to determine the influence of migraine on brain structure and assess the relationship between attack frequency and disease length to changes in the brain, Ashina says. As things stand, patients with WMAs “can be reassured.” Volumetric MRI “still remains a research tool.” But “patients with ILLs should be evaluated for stroke risk factors.”

Migraines are in the news lately. In June, Brigham and Women’s Hospital researchers presented a study at the International Headache Conference finding that, of 28,000 women, those experiencing migraines with aura are at increased risk for all types of stroke, both ischemic stroke involving blocked brain blood flow, and hemorrhagic stroke (bleeding in the brain). Specifically, during 15 years of follow up of 1,435 female migraine/aura sufferers, none of whom had heart disease at the outset, there were 528 strokes: 430 ischemic, 96 hemorrhagic.

In July, a PLOS One University of Pennsylvania study found that migraines with aura may be associated with an incomplete network of arteries providing blood to the brain called the circle of Willis, located near the back of the brain near the visual cortex.

“We do think it possible that white matter lesions (such as those described in the Neurology study) could be related to some of these abnormalities in blood flow and vessel structure which we identified,” says University of Pennsylvania neurologist Bruce Cucchiara. “But there is clearly a lot of work to do to sort this out. I think we are getting a more complex picture of what contributes to migraine. I'm not sure whether that is better!”