When comedian Markus Birdman woke up unable to see properly, he initially thought he had a hangover. But it turned out he had had a minor stroke, at the age of 40.

His experience became the basis of an Edinburgh festival stand-up routine and he now works raising awareness about the effects of strokes.

Recent research by the Stroke Association suggests a quarter of British people don't know that strokes occur in the brain. Four out of five stroke survivors surveyed said the people around them did not understand the impact of one.

Video journalist: Alex Stanger