Frequent sufferers of migraines have an increased risk of brain damage, researchers said today.

Professor Richard Lipton, from New York's Albert Einstein College of Medicine, said there was evidence that in some people, migraines got worse with time, leaving many severely disabled in their everyday lives.

He called on experts in the field to do more to actively target the prevention of migraines rather than simply managing the pain and symptoms.

Prof Lipton, speaking at the Migraine Trust international symposium in London, also said that his research had shown that over the course of just one year, 3% of headache sufferers progressed to a point where they had headaches most days.

He said these patients with chronic daily headaches were seriously disabled by their attacks.

"In the 1980s we focussed on the migraine attack and thought of it as an episodic disorder, " said Prof Lipton.

"In the 90s we recognised that migraine interfered with quality of life between attacks and that migraine sufferers had a predisposition to attacks. We came to think of it as a chronic episodic disorder.

"Today we must recognised that a subgroup of migraine sufferers have a progressive disorder with attacks that become more frequent and more disabling over time."

As well as his own research, Prof Lipton said he had reached this conclusion after work done at Leiden University in the Netherlands.

The Dutch researchers found that migraine sufferers were at an increased risk of brain lesions. They also found that the risk of suffering brain lesions increased the more frequent migraine attacks were.

The researchers concluded that this raised the possibility that migraine produced progressive changes in the brain.

Prof Lipton said his team had identified a number of risk factors for headache progression.

He said migraines were more likely to progress than other types of headache.

He also said that people with more than four headaches a month, those who were obese and people who took painkillers more than once per week were also particularly likely to experience progressively more attacks.

"The identification of individuals at high risk for headache progression creates opportunities to step in to stop this progressive natural history," Prof Lipton added.

Up to 15% of people in the UK experience migraines and twice as many women as men are sufferers.

Prof Lipton said migraine research was now where heart disease was two decades ago - at the beginning of "an exciting new era" where prevention was a real possibility.

He said the priority was to identify people with frequent disabling attacks to control and prevent attacks and avoid progression of the disease.

Other research being discussed at the meeting, attended by experts from around the world, looked at how imaging of the brain could lead to a better understanding of migraine.

Oxford University lecturer Dr Irene Tracey is developing brain imaging techniques which could eventually let doctors "see" a patient's pain.

It is also hoped that the new method - called functional magnetic resonance imaging - could lead to the development of new migraine therapies which target the right parts of the brain.

The researcher used a hot stimulus on the hands of volunteers, and using the equipment was able to see which parts of their brain lit up when they felt pain.

"In our experiments we have seen that the more or less painful something is, the more or less the regions in our brain that process pain signals activate.

"We can see an actual image of the pain someone is experiencing," Dr Tracey said.

The researcher said when someone described pain it could be very subjective and not related to the reality of the injury, tissue damage or disease.