A stroke occurs if an area of brain tissue is deprived of its blood supply causing brain cells to lose their supply of oxygen. This is usually caused by a blockage or burst blood vessel. Without oxygen, brain cells can become irreversibly damaged within minutes.
Unlike other cells in the body, if brain cells are irreversibly damaged then they are unable to heal themselves. The brain, however, is very adaptable and areas of the brain are capable of learning new tasks to compensate for the areas that have been damaged. Physiotherapy encourages this learning and to help the body re-learn normal movement patterns.
There are two types of stroke:
- Ischaemic (90%)
- Haemorrhagic (10%)
These are caused by a blockage within an artery. This blockage restricts the blood flow to an area of the brain, and therefore, brain cells in this area are damaged due to a lack of oxygen.
Haemorrhagic strokes (also known as brain haemorrhages)
These are caused when a blood vessel in the brain ruptures causing bleeding into an area of the brain. This causes a build up of pressure and damages the delicate brain tissue. Blood flow to neighbouring brain cells is restricted and these cells can also become damaged due to a lack of oxygen.