Vascular dementia is the second most common form of dementia after Alzheimer’s disease. It is caused by problems in the supply of oxygen to the brain. With blood being prevented from reaching the brain, due to poor circulation in blood vessels, cells die and lead to symptoms of dementia.
Vascular dementia is most commonly caused by a stroke. This happens when blood flow to the brain is blocked by a blood clot in an artery or when an artery bursts. This leads to oxygen depreivtion to the brain cells supplied by that vessel.
Vascular dementia often follows a ‘stepped’ progression, with symptoms remaining at a constant level for a time and then suddenly deteriorating. People may experience a series of small strokes, or mini strokes. This may cause temporary blindness or weakness in the arms of legs, often clearing quickly without any long term problems, but they may cause a build up of damage, thus causing dementia (multi-infarct dementia).
It affects different people in different ways and the speed of the progression varies from person to person. Some symptoms may be similar to those of other types of dementia, such as Alzheimer’s disease. Specifically however, people with vascular dementia may experience:
problems with speed of thinking, concentration and communication
depression and anxiety accompanying the dementia
symptoms of stroke, such as physical weakness or paralysis
memory problems (although this may not be the first symptom)
periods of severe (acute) confusion.
Other symptoms associated with vascular dementia may include:
visual mistakes and misperceptions (for example, seeing a rug as a pond)
changes in behaviour (such as restlessness)
difficulties with walking and unsteadiness
hallucinations (seeing or hearing things that aren’t there) and delusions (believing things that are not true)
problems with continence
psychological symptoms such as becoming more obsessive.
It is ALWAYS important to note in dementia that some of these symptoms may not always be direct consequences of the disease. Other factors play a part. For example, visual misperceptions may be the result of poor lighting or the particular way a home has been decorated, and some behavioural changes may be a consequence of care needs not being fully met.
How does vascular dementia develop?
Brain cells need a good supply of blood if they are to be healthy. Blood is delivered through a network of blood vessels called the vascular system. If the vascular system within the brain becomes damaged and blood cannot reach the brain cells, the cells will eventually die. This can lead to the onset of vascular dementia.
A number of conditions can cause or increase damage to the vascular system. These include high blood pressure, heart problems, high cholesterol and diabetes. This means it is important that these conditions are identified and treated at the earliest opportunity. Effective treatment of these conditions may significantly delay or stop the development of vascular dementia.
Types of vascular dementia
There are different types of vascular dementia. The difference between these types depends on what has caused the damage in the brain, and which part of the brain has been damaged.
A stroke occurs when the blood supply to part of the brain is cut off. This interruption in blood supply causes permanent damage to the brain. A stroke is usually the result of a burst blood vessel (known as haemorrhagic stroke) or a blood clot (known as an ischemic stroke).
The most common type of vascular dementia is called multi-infarct dementia, which is caused by a series of small strokes. These can be so tiny that the person might not notice any symptoms, or the symptoms may only be temporary. When vascular dementia develops after an obvious stroke, it is sometimes called post-stroke dementia (or ‘single-infarct dementia’).
Sub-cortical vascular dementia (small vessel disease or Binswanger’s disease)
Sub-cortical vascular dementia is sometimes referred to as small vessel disease. There is also a specific form of sub-cortical vascular dementia called Binswanger’s disease. Sub-cortical vascular dementia is caused by damage to the tiny blood vessels that lie deep within the brain. Symptoms may include difficulties walking, clumsiness, lack of facial expression and speech difficulties. Loss of bladder control early on in the disease is also common. These symptoms, however, are not always present and may come and go. Some people may experience sub-cortical vascular dementia as well as stroke.
Mixed dementia (vascular dementia and Alzheimer’s disease)
About 10 per cent of people with dementia have a type known as mixed dementia. A diagnosis of mixed dementia means that Alzheimer’s disease, as well as stroke or small vessel disease, may have caused damage to the brain. The symptoms of mixed dementia may be similar to either Alzheimer’s disease or vascular dementia, or may be a combination of the two.
Factors that can increase the risk of vascular dementia
Many of the factors that increase the risk of vascular dementia are the same as those that increase the risk of cardiovascular disease
The speed that vascular dementia progresses varies from person to person. Although the brain damage that causes vascular dementia cannot be reversed, it may be possible to slow the progression of the disease in a number of ways. These include:
taking medication to treat any underlying conditions, such as stroke, high blood pressure, high cholesterol, diabetes or heart problems
adopting a healthier lifestyle by stopping smoking, taking regular exercise, eating healthily, and drinking alcohol only in moderation
receiving rehabilitative support, such as physiotherapy, occupational therapy and speech therapy, to help the person maximise their opportunities to regain their lost functions.