Migraines caused by different blood supply to the brain

Research shows that those who suffer from migraines may have a different way that blood is supplied to the brain.

In the UK alone, it is estimated that there are 190,000 migraine attacks per day. Migraines cause insufferable pain and can affect day-to-day living dramatically too – they can cause dramatic mood changes, and the throbbing pain can make it difficult or even impossible to sleep, work – and yet researchers have found it extremely difficult to pinpoint what causes them.

Now research published in PLOS ONE indicates that migraine sufferers have different arterial networks supplying the brain and this could help explain the cause.

Blood supply to the brain is slightly different to other parts in that it is protected by connections between the major arteries, thereby helping to ensure bloodflow at all times.

These connections are named ‘circle of Willis’ after the doctor who first pinpointed them. It’s these connections that appear to be different in people with migraine. Researchers from the Perelman School of Medicine at the University of Pennsylvania, US, looked at 170 people – one group who had no headaches, another who had migraine with aura, and one more group who had migraine without aura. Migraine with aura is defined as being typified by visual disturbances such as flashes of light, blind spots or tingling in the hands or face.

While 51% of people without headaches had an incomplete circle of Willis, the figures were significantly higher for those who did: 73% of people with migraine with aura; and 67% of those with migraine without aura.

Interestingly, when the researchers did magnetic resonance imaging to assess bloodflow they found that abnormalities in the circle of Willis were most prominent in the part of the brain that deals with vision. This, say the researchers, might explain why migraine sufferers often report seeing distortions, spots or wavy lines. The researchers are keen to point out, though, that the differences in circle of Willis between individuals is unlikely to be the only factor leading to migraine, and that other factors are almost certainly involved too. They do, however, suggest that checking the circle of Willis in patients could help pinpoint which contributory factors a patient has, thereby helping researchers move forward with testing different types of treatment.

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