Vascular
Dementia
Introduction
Alzheimer's disease is the most common of a large group of disorders known as "dementias." It is an irreversible disease of the brain in which the progressive degeneration of brain cells causes thinking ability and memory to deteriorate. Alzheimer's disease also affects behaviour, mood and emotions, and the ability to perform daily living activities.
There is currently no cure for Alzheimer's disease, but there are treatment options and lifestyle choices that can slow its progression and, within the next five years, treatments are expected that may well stop the disease in its tracks! Also, the pursuit of new research strategies should one day help restore some lost function and memory.
Alzheimer's disease progresses through early, middle and late stages before reaching the final end of life stage. However, identifying the transition from one stage to another is often difficult. Not only does the disease usually progress slowly, but the symptoms related to each stage tend to overlap and the order in which they appear and how long they last varies from person to person.
The duration following diagnosis is usually seven to ten years. However, when the diagnosis is delayed, as it may be if the affected person fails to see a doctor early on, the disease duration is shorter than this. Conversely, as the ability to diagnose Alzheimer's disease improves and people become more willing to be assessed, survival times following diagnosis are lengthening.
"Related dementias" resemble Alzheimer's disease in that they also involve a progressive degeneration of brain cells that is currently irreversible. They include the dementia associated with Vascular Dementia (the second most common dementia after Alzheimer's disease), Frontotemporal Dementia, Creutzfeldt-Jakob Disease, Lewy body Dementia, Parkinson's disease, and Huntington disease.
Sometimes a person may have symptoms such as sudden onset of memory loss, behaviour changes, or difficulties with speech and movement. These symptoms may suggest a dementia other than Alzheimer's disease. Vascular Dementia is one of these dementias. In any event a person should always seek a thorough medical assessment if any of these symptoms are present.
Regardless of the type of dementia, individuals are encouraged to obtain information and support from the Alzheimer Society.
What
is Vascular Dementia?
Vascular Dementia (VaD), also called multi-infarct dementia, occurs when the cells in the brain are deprived of oxygen. A network of blood vessels called the vascular system supplies the brain with oxygen. If there is a blockage in the vascular system, or if it is diseased, blood is prevented from reaching the brain. As a result, cells in the brain die, leading to the symptoms of dementia. After Alzheimer's disease, VaD is the second leading form of dementia, accounting for up to 20% of all cases.
When Alzheimer's disease and VaD occur at the same time, the condition is called mixed dementia.
How
does Vascular Dementia affect the person?
Stroke and Vascular Dementia
Stroke is a common cause of VaD. A stroke occurs when blood flow in the brain is blocked. When this occurs, the brain cells are deprived of oxygen and die. Strokes can be large or small, and can have a cumulative effect (each stroke adding further to the problem). Depending on the specific brain areas deprived of oxygen, strokes can affect the person's ability to walk, can cause weakness in an arm or leg, slurred speech or emotional outbursts.
VaD usually has a sudden onset. Impairment may occur in steps, where functioning can deteriorate, stabilize for a time and then deteriorate again. The cognitive symptoms may vary, affecting some areas of the brain more or less than others (e.g., language, vision or memory). Urinary difficulties are common in people affected by VaD.
Binswanger's disease
Binswanger's disease is a rare form of VaD that is caused by damage to blood vessels deep in the brain's "white matter." High blood pressure plays an important role in Binswanger's disease.
How is Vascular Dementia assessed?
If VaD is suspected, the doctor will often order scans of the brain in order to check for blockages or narrowing of blood vessels in the brain.
What
are the risk factors for Vascular Dementia?
Both men and women can be affected by VaD. Risk
factors for VaD include:
-
over age 65
- having high
blood pressure (hypertension)
- heart
disease
- diabetes
Smoking, being overweight, having elevated cholesterol levels and a family history of heart problems may also increase the risk of stroke, which increase the risk of VaD. Mini-strokes (sometimes referred to as transient ischemic attacks or TIAs) are warning signs that a stroke may be imminent. Temporary loss of vision, speech, strength or brief episodes of numbness may indicate a TIA.
Routine brain scans in a group of middle-aged people showed that 10 percent of them had suffered a stroke without knowing it, raising their risk for further strokes and memory loss. Such silent cerebral infarctions (SCIs, or silent strokes) are brain injuries caused by a blood clot that interrupts blood flow to the brain. In many instances, silent strokes are considered to constitute a risk factor for VaD. People with atrial fibrillation, the most common type of irregular heart beat in people over 65, have more than twice the rate of these silent strokes.
Knowing the risk factors for VaD is important because often they may be treated to reduce the risk of stroke. Risk factors can be reduced by adopting a healthy lifestyle that includes regular physical activity, eating well, avoiding smoking and reducing stress. Medications can control high blood pressure, diabetes and heart disease.
Is
there treatment?
After a person has a stroke, medication may be prescribed to improve blood flow to the brain and reduce the risk of further stroke. A person may also benefit from different therapies to help with movement and speech, such as physiotherapy, occupational therapy or speech therapy. Aside from the treatment of the underlying causes of VaD such as hypertension, high cholesterol and diabetes, some physicians routinely recommend the use of medications called cholinesterase inhibitors.
For
more information:
[The contents of this document are provided for information purposes only, and do not represent advice, an endorsement or a recommendation, with respect to any product, serve or enterprise, and/or the claims and properties thereof, by the Alzheimer Society of Canada. The Information Sheet is not intended to replace clinical diagnosis by a health professional.]
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