Stroke occurs when the blood supply to a portion of the brain is stopped or if there is bleeding in and around the brain. It can severely affect the entire body. There are several causes of strokes like blood clots in the neck or brain, or if artery bursts within the brain. When you see someone with a sudden and temporary weakness or numbness in the face, arm or leg then it can be due to a stroke. Even a temporary loss of eyesight in one eye, difficulty with speech or difficulty understanding others, dizziness, and unexplained headaches can be a reason for a stroke.