What causes vascular dementia?
Vascular dementia is caused by reduced blood flow to the brain, which damages and eventually kills the brain cells.
There are several different types of vascular dementia. They differ in the cause of the damage and the part of the brain that is affected as follows:
Caused by a stroke which happens when the blood supply to a part of the brain is suddenly cut off. In most strokes, a blood vessel in the brain becomes narrowed and is blocked by a clot. The clot may have formed in the brain, or it may have formed in the heart (if someone has heart disease) and been carried to the brain.
Not everyone who has a stroke will develop vascular dementia, but about 20 per cent of people who have a stroke do develop this post-stroke dementia within the following six months
Caused by a smaller stroke where the stroke leads to the death of a small area of tissue in the brain. This area is known as an infarct. Sometimes just one infarct forms in an important part of the brain and this causes dementia.
Caused by lots of “mini-strokes” that cause tiny, but widespread, damage to the brain.
Caused by narrowing of the small blood vessels deep inside the brain.
How vascular dementia affects people varies depending on the different underlying causes and which part of the brain has been damaged.
The most common early signs of vascular dementia include:
- Slowness of thought.
- Difficulty planning, organising or making decisions.
- Speech may become less fluent.
- Problems with attention and concentration.
- Mood or behavioural problems.
- Possible mild problems recalling recent events.
Vascular dementia will generally get worse, although the speed and pattern of this decline vary. Stroke-related dementia often progresses in a ‘stepped’ way, with long periods when symptoms are stable and periods when symptoms rapidly get worse. This is because each additional stroke causes further damage to the brain. Subcortical vascular dementia may occasionally follow this stepped progression, but more often symptoms get worse gradually, as the area of affected white matter slowly expands.
Possible advanced symptoms include:
- Severe slowness of thought.
- Feeling disorientated and confused.
- Memory loss and difficulty in concentrating.
- Difficulty finding the right words.
- Severe personality changes, such as becoming aggressive.
- Depression, mood swings and depression.
- Frequent falls.
- Urinary incontinence.
- Occasionally people will experience hallucinations
The average survival time from diagnosis is around four years. Most people will die either from complications of dementia, such as pneumonia, or from a subsequent stroke.