Scientists have discovered that migraines may affect the long-term structure of the brain and increase the risk of brain lesions, according to a study published in the journal Neurology.

Researchers from the University of Copenhagen in Denmark analyzed six population-based studies and 13 clinic-based studies to see whether there was a link between migraines and brain lesions, silent abnormalities or brain volume changes.

The study authors looked at MRI brain scans of patients with common migraines or migraines with aura. Migraine with aura is when a person experiences symptoms before the onset of the migraine. These scans were compared with those of people not suffering from the disorder.

The results of the study revealed that those who had migraines with aura showed a 68% increased risk of white matter brain lesions, compared with those who did not have migraines.

Patients who experienced common migraines showed a 34% increased risk of brain lesions compared with those not suffering from migraines.

Infarct-like abnormalities in the brain - symptoms that indicate a disruption in blood flow to the brain - increased by 44% in those who had migraines with aura compared with those who had migraines without aura.

Additionally, brain volume changes were more prevalent in both people with common migraines and migraines with aura than those without the conditions.

The study authors explain:

"The present review suggests that migraine may be a risk factor for structural changes in the brain.

In comparison with non-migraine controls, migraineurs have more WMAs (white matter abnormalities), ILLs (infarct-like lesions), and volumetric changes in GM (grey matter) and WM (white matter) regions."

A common disorder with long-term effects

According to the Migraine Research Foundation, migraine ranks in the top 20 for the world's most disabling medical illnesses. Every 10 seconds, a person in the US visits the emergency room as a result of a headache or migraine.

For a disorder that is so common, the researchers stress that it is important to understand the long-term effects a migraine can have on the brain.

They add that guidelines from the American Academy of Neurology and the US Headache Consortium suggest that people with migraines who have normal neurological examinations do not need routine MRI scans.

"Only patients with atypical headache, a recent change in headache pattern, other symptoms (such as seizures), or focal neurologic symptoms or signs are recommended for MRI of the brain," the researchers say.

"Patients with WMAs can be reassured. Patients with ILLs should be evaluated for stroke risk factors. Volumetric MRI remains a research tool."

Dr. Messoud Ashina of the University of Copenhagen and lead study author says that further research is needed to fully determine the link between migraine and long-term brain structure.

"Migraine affects about 10 to 15% of the general population and can cause a substantial personal, occupational and social burden," he adds.

"We hope that through more study, we can clarify the association of brain structure changes to attack frequency and length of the disease. We also want to find out how these lesions may influence brain function."

This year, a study from italian researchers also found that migraine patients have brain abnormalities, compared with those who do not have the disorder.

Other recent research from the University of Pennsylvania suggests that the cause of migraines could be due to the structure of brain arteries that protect the supply of blood to the brain.