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 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.
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
Smoking, being overweight, having elevated cholesterol levels and a family history of heart problems may also increase the risk of stroke, which increases 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.