Vascular disease occurs where blood vessels are damaged and the supply of oxygen is at risk. If oxygen supply fails in the brain, brain cells are likely to die leading to a series of mini strokes (infarcts) and possible vascular dementia. Vascular dementia accounts for 20%-30% of all cases of dementia.
The mini strokes that cause vascular dementia are often so slight that they cause no immediate symptoms, or they may cause some temporary confusion. However, each stroke destroys a small area of cells in the brain by cutting off its blood supply and the cumulative effect of a number of mini strokes is often sufficient to cause vascular dementia. Vascular dementia and Alzheimer's disease frequently occur together and they may often act in combination to cause dementia.