Difference in the structure of the brain blood vessels may cause migraine

Migraine is a cause of significant disability in people around the world and various theories have been postulated to explain it. While earlier it was believed that migraine was caused due to abnormal dilatation of the cerebral blood vessels, later it was thought that migraine was a result of abnormal neuronal activity in the brain. However, a new study published in the latest issue of the journal PLoS One has found that a difference in the structure of the blood vessels supplying the brain may be the actual reason behind migraine. The study was led by researchers from the Perelman School of Medicine at the University of Pennsylvania.

For their study, the researchers examined 170 people in three groups. The first group consisted of people who suffered from migraine associated with aura, the second group consisted of people who had migraine but no aura and the third group consisted of people with no history of migraine. All the participants of the study were made to undergo a magnetic resonance angiography to analyze the structure of the blood vessels in the brain. They also underwent Arterial Spin Labeling (ASL) which is a non-invasive technique pioneered at the University of Pennsylvania and used to measure the changes in the blood flow. 

The researchers found that the Circle of Willis was incomplete in 73 percent of people with a history of migraine with aura. It was incomplete in 67 percent of people who suffered from migraine without aura and incomplete in 51 percent of people who had no history of migraine. Circle of Willis is a series of connection between the major arteries supplying the brain. The researchers have opined that because of the structural alteration of the cerebral blood vessels, the brain becomes more susceptible to the changes in the blood flow resulting from any cause. This triggers abnormal neuronal activity leading to migraine.

The researchers also found that the structural abnormality of the blood vessels was most common in the posterior region of the brain where the visual cortex is situated. This may explain the multiple visual symptoms like wavy lines, spots and distortions seen during an aura.

Editor: Dr. Bimal Rajalingam MBBS DNB (Resp Med)

Tuesday, July 30, 2013
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