Stroke is a disease that affects the vessels that supply blood to the brain.
When a part of the brain does not get the blood flow it needs, nerve cells in the affected area can't function and die within minutes. That means the part of the body controlled by these cells stops working. When there is nerve or tissue damage on the left side of the brain, where the primary language areas are located in most people, a stroke patient can be left with the inability to speak. Stroke is the third leading killer of Americans, taking 160,000 lives every year. It is also the largest cause of neurological crippling and the leading cause of adult disability in the United States.