A stroke stops the flow of blood to part of your brain. Afterward, damaged brain tissue can make it hard to think, speak, remember, or pay attention. It’s called vascular dementia. This can also happen with a series of small strokes over time. Things that raise your risk of stroke like high blood pressure, heart disease, and smoking may also cause this type of dementia. If you think you’re having a stroke, remember FAST: Face drooping, Arm weakness, Speech problems, Time to call 911.