What is Vascular Dementia and how does it vary from Alzheimer’s disease?
Alzheimer’s is now a well-known term and in many cases has become the “catch-all” phrase for dementia. Yet dementia comes in many forms. Vascular Dementia is the second biggest cause of dementia in the UK yet it remains little recognised. While the symptoms may be similar to Alzheimer’s there are important differences which can have an impact both on how the disease develops and its possible treatment.
So what is Vascular Dementia?
Vascular dementia is the result of blocked or reduced flow of blood to the brain depriving the brain cells of vital oxygen and nutrients.
Unlike Alzheimer’s, where the cause remains unclear, vascular dementia is caused by a specific, acute event (or series of events) such as stroke or TIAs (mini strokes) where the flow of blood to the brain is interrupted, or, small vessel disease which is the result of narrowing or blockages of the blood vessels deep inside the brain, and develops gradually over time.
The onset of symptoms can be gradual or sudden depending on the degree of damage to the blood vessels and the particular part of the brain affected. The symptoms of dementia may become immediately obvious after a major stroke, but in the case of small vessel disease or a series of mini-strokes, where the reduction of blood flow to the brain is much more gradual, the symptoms may go completely unnoticed to start with and develop only over time.
The symptoms of Vascular Dementia
After a major stroke, the symptoms of dementia are likely to occur at the same time as the physical symptoms of stroke such as paralysis on one side of the body, difficulty walking and headache. Symptoms may include:
- Communication difficulty – trouble speaking or understanding speech
- Loss of vision
In the case of Multi-infarct dementia (the type of dementia caused by a series of mini-strokes) or Subcortical Vascular dementia (small vessel disease) the symptoms are likely to appear as far more gradual changes in thinking and behaviour as the damage to the brain accumulates over time. Early signs may include:
Depression and anxiety often go hand in hand with vascular dementia as the person with the symptoms is aware of the difficulties they are facing, and this anxiety can in itself make the cognitive symptoms worse.
It is important ALWAYS to consult your doctor if you experience any symptoms – even if they appear to go away after a time –because the symptoms may be caused by temporary interruptions in the blood flow to the brain, which left untreated, could cause permanent damage.
How does Vascular Dementia differ from Alzheimer’s disease?
The main difference between these 2 forms of dementia is in the way in which the symptoms begin and then progress.
In Alzheimer’s disease, the symptoms tend to appear gradually, then worsen in a steady downward path. The rate of decline is usually consistent across all cognitive abilities.
With Vascular Dementia, the symptoms may appear gradually or suddenly, but will then stabilize for a period of time, until another stroke causes a further sharp decline before symptoms again stabilize. In some cases, cognitive changes may even improve temporarily during recovery from the acute phase of a stroke as the brain generates new blood vessels, and brain cells outside the damaged region take on new roles. This uneven pattern through the disease is often described in terms of a stepped pattern of decline, wheras the decline in Alzheimer’s typically follows a straight continuous downward path.
Another important difference lies in the fact that people with vascular dementia tend to maintain their personality, and retain certain abilities until much later stages of the disease.
This is because Vascular Dementia affects distinct parts of the brain, while Alzheimer’s tends to affect the whole brain. For this reason, memory loss may not be a significant symptom in Vascular dementia if that is not the region of the brain where blood flow is reduced.
Recognising the symptoms, and trying to predict the course of the disease is made more complicated by the fact many people with Alzheimer’s also have vascular disease. The Alzheimer’s Society estimate that about 10% of people with dementia have a mixed form of the disease where Alzheimer’s disease plus stroke or small vessel disease have together caused damage to the brain.
Treatment for Vascular Dementia
At the time of writing this article, no drug treatments are specifically approved for Vascular Dementia in either the UK or United States. There is some clinical trial evidence that certain drugs approved for Alzheimer’s disease may offer a modest benefit for the treatment of mixed dementia, and in certain cases these may be prescribed, particularly when Alzheimer’s disease is predominant.
Treatment therefore takes 3 main forms:
- Lifestyle changes to reduce the risk factors
There is substantial evidence that effective treatment of the risk factors for dementia may improve outcomes and help postpone or prevent further decline. Improving diet, taking regular exercise, avoiding obesity and cutting out tobacco can all play a major part in an effective treatment programme.
- Medication to treat any underlying conditions such as high blood pressure, diabetes, stroke, heart problems or high cholesterol.
These might include anticoagulants such as warfarin, antiplatelet agents such as aspirin, medications to decrease viscosity (blood thickness), or even possible surgery for severe cases.
- Rehabilitation support
Multi-agency support (Occupational Therapy, Speech and Language Therapy, and Physiotherapy) can help maximise opportunities to regain lost function and postpone further decline.