Migraines Linked to Changes in Brain

August 29, 2013

News Review From Harvard Medical School -- Migraines Linked to Changes in Brain

The brains of people with migraines look a bit different than other brains, a review of research concludes. The review looked at 19 studies. All of them examined people's brains using magnetic resonance imaging (MRI). The images showed that people who have migraines are more likely than others to have changes in the brain's white matter. These areas help to carry signals within the brain. People with migraines also had more areas in the brain that looked like previous strokes. Researchers said they don't know why changes in white matter are more common in people with migraines. They don't know if migraines caused the changes, or if the changes caused the migraines. Or something else could have caused both. They said they have no evidence that the changes affect people's health. But experts interviewed by HealthDay News cautioned that anyone with evidence of a prior stroke should get checked by a doctor. The journal Neurology published the study. HealthDay wrote about it August 28.

By Robert H. Shmerling, M.D.
Harvard Medical School

What Is the Doctor's Reaction? 

Migraine headaches are common, affecting up to 15% of the U.S. population.

Yet migraine is also a mysterious condition. The cause is unknown. The course of the illness is hard to predict. And it's impossible to forecast how often attacks will come or how severe they will be.

Fortunately, most people with migraines have no long-term problems related to them. The headache is temporary, and once it's over the brain and body function normally. Stroke and other complications have been reported, but they are very rare. Migraine is generally considered to be bothersome for short periods of time, but with no lasting complications.

But a new study calls this into question. Its results raise the possibility that migraines may permanently change the structure of a person's brain.

The medical journal Neurology published the study. Researchers reviewed 19 previous studies that compared brain MRI scans from people with and without migraines. They found that people with migraines had:

• Far more abnormalities in the "white matter." These are the deep parts of the brain responsible for learning and rapid nerve communication between different parts of the brain.
• Smaller brain volume.
• An even higher risk of an abnormal brain MRI if the person also tended to see an "aura" around the time of the headaches. These are other symptoms that may occur before or along with a migraine. Examples may include flashing lights, bright lines or blurry vision. The chance of having abnormal areas of white matter was 68% higher for people who had migraines with aura than for people without migraines. The risk was increased 34% among those with migraines alone. 

The importance of these findings is uncertain. Perhaps the biggest question is whether the abnormal areas seen on brain MRIs were there before the migraines even began. If they were, these structural changes could have actually caused migraines rather than being caused by them.

We also don't know whether the abnormal areas of the brain cause the brain to function abnormally. It's been known since the invention of MRIs that healthy people can have minor abnormalities with no impact on health or function. Perhaps these findings among people with migraines are also of little consequence.

Still, this is the sort of finding that could change the way we think of migraine. Perhaps we will find out that migraines cause permanent, structural changes that can be seen on an MRI scan. If that's the case, and if these changes result in impaired brain function, we'll need to determine whether treatment can prevent these changes. 

What Changes Can I Make Now?

Let your doctor know if you have symptoms that could be caused by migraines. These include: 

• A throbbing headache that comes and goes
• Headaches that get worse with loud noise or bright lights
• Headaches that occur along with nausea or vomiting
• Aura before or at the same time as the headache – This may include blurry vision or flashing lights at the edge of your peripheral vision.
• Exhaustion after the headache 

Many people with migraines find they can limit the number of migraines they have by: 

• Avoiding either an excess of caffeine or a sudden cutback in consumption
• Avoiding certain foods (such as salty or processed foods) or additives (such as MSG or sulfites)
• Limiting stress
• Getting enough sleep
• Avoiding medicines that contain hormones, such as birth control pills
• Getting regular exercise
• Getting acupuncture treatments or massage

Other migraine triggers may include travel, or a change in weather or altitude.

Several medicines can be used to treat migraines. Some are taken as needed, when headaches (or an aura) develop. Others are taken regularly to prevent migraines. The best approach depends on several factors. They include: 

• How severe your symptoms are
• Your preferences about medicine use
• Side effects of medicines
• Cost of medicines
• Other medical problems

Review all of your options with your doctor. Be sure you understand the pros and cons of each.

What Can I Expect Looking to the Future? 

This latest study was not able to say whether migraine headaches caused abnormal areas in the brain or whether these abnormalities may have caused the migraines. It's even possible that the treatments for migraine led to the brain changes. You can expect future research to sort this out.  

The new study also did not determine whether the abnormal areas seen on MRI actually matter. If migraine headaches are linked with changes in brain structure, we need to know what effect, if any, these changes have on brain function.

Considering how many people have migraine headaches, there is a lot riding on this area of medical research.