Silent strokes tied to memory loss among older adults (Video)

A massive stroke - when blood vessel in the brain bursts - can leave someone paralyzed, mute or dead. The World Health Organization says at least six million people died from strokes in 2008 alone. But not everyone recognizes when they've had a mild stroke, which may not cause any symptoms. New research indicates these so-called "silent" strokes affect more people than previously thought. And they can cause memory loss in one out of four adults.