A stroke occurs when the supply of blood to your brain is disrupted. Without blood flow, the brain is starved of oxygen and cells quickly die.
Ischaemic stroke is more common and occurs when a clot forms somewhere in the body, most commonly the heart. When the clot moves and reaches the brain, it gets stuck in one of the blood vessels, cutting off blood supply to that part of the brain. A build-up of cholesterol and other fatty material known as 'plaque' along artery walls, often in the neck, can also prevent blood from getting through, causing an ischaemic stroke.
Always call 000 in an emergency.