People with migraines may also be suffering from some brain damage as brain cells swell and become starved of oxygen, researchers say.

This damage is simililar to the type that can occur with concussions and after strokes, the researchers report online in the journal Nature Neuroscience.

They say their finding may help to explain why migraine sufferers have a higher risk of stroke.

It may also suggest that migraine patients should not simply get pain relief but also drugs that prevent the migraine, which is often preceded by aura, a series of visual disturbances that can include flashes of light or black spots.

The research, which was done in mice, suggests giving oxygen may help reduce the damage, the international team says.

Giving the mice rich doses of oxygen seemed to shorten the duration of the wave of brain effects seen in CSD, the researchers say.