A silent stroke is a stroke that has no or nearly no symptoms, although sudden difficulty with memory and mobility are possible signs of such a stroke, according to WebMD. The damage from a silent stroke is visible on a brain scan.
Studies show signs of silent strokes in about 10 percent of middle-aged adults, as explained by WebMD. Risk of a silent stroke increases with high blood pressure and an irregular heartbeat. People can reduce the risk of both regular strokes and silent strokes by taking steps to treat high blood pressure, eating a healthy diet and engaging in regular exercise. Silent strokes can cause permanent damage.