Vascular dementia which is the second most common dementia sub-type after AD is caused by damage to the blood vessels that supply brain cells leading to loss of blood flow to the brain. There are a number of different causes of vascular dementia.
Vascular dementia can be caused by a series of small strokes that often go unnoticed. These mini-strokes, also referred to as transient ischemic attacks (TIAs), result in temporary, partial blockages of blood supply and brief impairments in consciousness or sight. Vascular dementia can have a step-wise progression where symptoms worsen gradually as a result of further minor strokes or other conditions that affect smaller blood vessels leading to cumulative damage.
One single large stroke can sometimes cause vascular dementia depending on the size and location of the stroke. This type of vascular dementia, called strategic infarct dementia, is characterized by (following the stroke) the sudden onset of changes in thinking skills and behavior. Symptoms vary depending on the area of the brain affected by the damage. Providing no further strokes occur, symptoms may stabilize and in some cases can improve.
Another form of vascular dementia is called subcortical dementia, or Binswanger’s disease. This is associated with disease in the brain’s small blood vessels system and damage to subcortical areas of the brain. It can be a consequence of untreated high blood pressure or diabetes leading to vascular disease. Symptoms often include deterioration of reasoning and thinking skills, mild memory problems, walking or movement problems and behavioural changes. Subcortical dementia is usually progressive with symptoms getting worse over time as more vascular damage occurs.
It is possible to have a dementia caused by both vascular disease and Alzheimer’s disease. This is commonly known as ‘mixed’ dementia.
Factors that increase your risk of heart disease and stroke also raise your risk of getting vascular dementia. Controlling the following factors can help to lower your chances of developing vascular dementia:
As with Alzheimer’s disease there is no specific test that can diagnose vascular dementia. A diagnosis is normally based on a range of information including clinical history, brain scans and neuropsychological testing. Early detection and accurate diagnosis are important as vascular dementia is at least partially preventable. Currently, there is no known cure, but it is encouraging to know that making certain lifestyle changes and using practical strategies may help prevent strokes, compensate for cognitive loses, and slow its development.