Definition

A stroke is the sudden death of cells in a limited part of the brain caused by a reduced flow of blood to the brain.

Description

Blood brings oxygen and nutrients to brain cells and also removes waste products from cells. A stroke occurs when blood flow is interrupted to part of the brain. Without blood, brain cells quickly begin to die. The effects of a stroke depend on the part of the brain affected. A stroke may cause paralysis, speech problems, loss of memory or reasoning ability, coma, or death.

More than half a million people in the United States experience a stroke each year. Stroke is the third leading cause of death in this country and the leading cause of disability. Two-thirds of all strokes occur in people over the age of sixty-five. They affect men more often than women, and blacks more often than...