A stroke is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia (lack of blood supply) caused by thrombosis or embolism or due to a hemorrhage. A quick way of determining if the person has had a stroke is to ask them to Smile, Stick out their tongue, Say a sentence, and Stretch up their arms. If they have any difficulty with these 4 items, call 911 immediately. The faster someone has treatment for a stroke, the better the outcome.