The mind-numbingly painful headaches known as migraines may alter the structure of your brain.

Those excruciating episodes can cause mysterious brain lesions, temporarily destroy gray matter and increase the risk of stroke, according to a study published today in the journal Neurology. Though migraines affect a large segment of the population — at least 18 percent of women and 6 percent of men will have a migraine at some point — scientists are unsure as to why they might change the brain’s structure.

“We found that migraine might be a risk factor for structural changes in the brain, [but] at this point, we don’t know what these abnormalities mean for patients with migraines,” said Sait Ashina, MD, a neurologist at Beth Israel Medical Center in New York City and co-author of the study.

Pain in Your Brain

Researchers did a meta-analysis of eight different studies, compiling and summarizing the individual results into one large set of data. The data suggest that patients who have migraines with “auras” are 70 percent more likely to have some sort of brain damage, said Richard Lipton, MD, a neurologist at the Montefiore Medical Center in New York City and also a co-author of the study.

There are two types of migraines — migraines with aura and migraines without. Auras usually indicate that a migraine is on the way and may cause a patient to see flashing lights, bright zig-zag lines or spots of black.