When comedian Marcus Birdman woke up unable to see properly, he initially thought he had a hangover. But it turned out that he had a mild stroke at the age of 40.
His experience became the basis of the Edinburgh stand-up festival and he is now working on raising awareness about the effects of stroke.
A recent study by the Stroke Association suggests a quarter of the British people do not know that strokes occur in the brain. Four out of five surveyed stroke survivors said people around them did not understand the impact of one.
Video journalist: Alex Stanger