Strokes come in all different sizes. Some are so minor they aren't even noticed, and are only evident via brain imaging technology. Others are so severe they cause complete physical and mental impairment, or are fatal. Recovery can take a long time and requires a tremendous amount of patience and care.
The majority of strokes are called ischemic strokes and occur when arteries in the brain become narrowed and/or clogged, which reduces blood flow to the brain.