Vascular dementia -- can you explina how this happens?

Vascular dementia: This problem often happens in people with longstanding hypertension with damage to blood vessels all over their body, not just in their brains. Atherosclerotic plaque builds up and becomes inflamed. There can be blockages in small vessels that nourish the brain, causing small strokes that injure or kill brain tissue. Repeated episodes leads to more and more cognitive and memory loss.