|Does Migraine Cause Brain Damage?|
By Melissa Lee Phillips |
Neuroscience for Kids Consultant
March 5, 2004
Treatment for migraine usually targets the disease's symptoms. Migraine medications are designed to reduce pain and restore functioning ability. But some people with migraine might be interested in a treatment that does something further: prevents brain damage. The risk of developing certain types of brain lesions is increased for some migraine sufferers, according to a study published in the January 28, 2004, issue of the Journal of the American Medical Association. The study's authors speculate that this brain damage may be caused by migraine attacks.
Migraine is a neurological disorder characterized by repeated, disabling headaches. About a third of people with migraine also experience a sensory disturbance called an aura, before or during headache onset. These sensory symptoms are usually visual, such as flashing lights or blind spots, but they can also be auditory. Previous research has hinted at a possible association between migraine and brain lesions. In this study, researchers, led by Mark C. Kruit, of Leiden University in the Netherlands, examined Dutch adults. These people were divided into three groups: those who had migraine with aura, those who had migraine without aura, and a control group who had never suffered from migraine.
Kruit and his co-workers used magnetic resonance imaging (MRI) to spot brain lesions in their research subjects. They looked for two different types of lesions: infarcts and white matter lesions. Both types of lesions are small patches of dead brain cells. An infarct is a focused area of tissue that has died from blood and oxygen deprivation. Infarcts are sometimes called "little strokes" -- they involve the blockage of blood supply to the brain, as in stroke, but the person is not aware of what has happened.
White matter lesions, which are often seen in people with Alzheimer's disease or multiple sclerosis, are usually more diffuse areas of cell death. Their underlying cause is not certain, although a decrease in blood flow has been implicated. White matter lesions involve only neuron axons; infarcts also destroy cell bodies.
The researchers found that more people with migraine than without migraine had infarcts in their brains. But this result was not statistically significant -- that is, the higher rate of infarcts in the migraine group could have been simply a coincidence.
The reseachers next checked for a correlation between migraine and infarcts in a specific part of the brain called the cerebellar region of the posterior circulation territory (PCT). The PCT, which is the vessel system that feeds blood to the back of the brain, has been cited in previous studies of stroke in people with migraine. Since severe infarcts are one cause of stroke, the PCT was a logical place to look. In this region only, there was significant relationship: patients with migraine were seven times as likely to have an infarct in the PCT. And their chances were even higher if they had either migraine with aura or had attacks more than once a month. The worst case was for those who had both migraine with aura and had attacks frequently: these people were almost 16 times as likely as controls to have an infarct in the PCT.
When Kruit and his team inspected diffuse white matter lesions in the brains of their subjects, they found a significant correlation with migraine only in women, and only if the lesions were in the periventricular area of the brain, right around the ventricles. For these people, the increased frequency of migraine attacks was associated with more white matter lesions, just as it was with infarcts in the PCT.
The fluid-filled ventricles
in the middle of the brain.
(Image adapted from Biodidac)
| Women did not show a correlation between migraine
and white matter lesions in other parts of their brains, and men with
migraine were no more likely than controls to have white matter lesions
anywhere in their brains. The authors do not know why this difference
arises between women and men. But, they point out, three times as many
women have migraine as men, and previous studies have indicated that
migraine can be a risk factor for stroke in women, but not men. So it
seems that there may be some underlying sex differences in migraine. |
The researchers speculate that the trauma the brain experiences during migraine attacks is directly killing brain tissue, although they acknowledge that there could be a third, unseen factor contributing to both migraine and brain lesion development.
In the past, physicians have generally viewed migraine as an episodic disorder--patients experienced attacks from time to time, but they didn't seem to be getting any worse. This study, in conjunction with previous work, indicates that, at least for some people, migraine is progressive: more attacks mean more brain damage. And although not all migraine patients appear to be at risk, some may experience not only debilitating pain and visual disturbances, but also the decay of small parts of their brains.
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