The most common form of a Stroke is the result of a sudden disruption of the flow of blood to parts of the brain.
When blood cannot reach parts of the brain, the oxygen supply to those areas is cut off and the brain cells die (infarct). Less frequently, blood vessels burst and blood spreads into nearby brain areas (haemorrhage). The result of these processes is a Stroke.
Functions normally controlled by these damaged brain areas are affected. In many cases, unconsciousness and/or partial paralysis may occur. This is often the immediate outward sign that a Stroke has occurred.