Stroke (also called a "cerebrovascular accident," or CVA) is a disease of the blood vessels in and around the brain. It occurs when part of the brain does not receive enough blood to function normally (called "ischemia") and the cells die (infarction), or when a blood vessel ruptures (hemorrhagic stroke). Ischemia is more common than hemorrhage and can be caused when a vessel (artery) supplying blood to the brain becomes narrowed by a fatty deposit called plaque. This is also called atherosclerosis. This plaque can rupture and form a blood clot that along with pieces of plaque can travel to blood vessels further in the brain and block them causing a stroke. In addition, clots can arise in the heart (called a "thrombus") and travel to the brain (called an "embolus"). Permanent damage to brain cells can result.
The symptoms of stroke vary, depending on which part of the brain is affected.
- Common symptoms of stroke are sudden paralysis or loss of sensation in part of the body (especially on one side), slurred speech, partial loss of vision or double vision, or loss of balance. Loss of bladder and bowel control can also occur.
- Other symptoms include decline in "cognitive" mental functions such as memory, speech and language, thinking, organization, reasoning, or judgment.
- Changes in behavior and personality may occur.
- If these symptoms are progressive and severe enough to interfere with everyday activities, they are called dementia or "major neurocognitive disorder."
Cognitive decline related to stroke is usually called vascular dementia or vascular cognitive impairment to distinguish it from other types of dementia. In the United States, it is the second most common form of dementia after Alzheimer's disease. Vascular dementia may be preventable, but only if the underlying vascular disease (such as hypertension) is recognized and treated early.
People who have had a stroke have a far greater risk of developing dementia than people who have not had a stroke. About 1 in 4 people who have had a stroke will go on to develop signs of dementia.
Vascular dementia is most common in older people, who are more likely than younger people to have vascular diseases. It is more common in men than in women.