Vascular dementia is the second most common cause of dementia, after Alzheimer's disease, according to the National Institute of Neurological Disorders and Stroke.
It is caused by blockages in the brain's blood supply, often from multiple strokes, and can severely affect memory and cognitive functioning.
It accounts for up to 20 percent of all dementias and, according to the Mayo Clinic Web site, afflicts 1 percent to 4percent of people over 65.
It may also result from genetic diseases, infection of a heart valve or amyloid angiopathy, a process that causes bleeding in the brain's blood vessels.
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The incidence of vascular dementia increases with advancing age and is similar in men and women.
Symptoms of vascular dementia often begin suddenly, frequently after a stroke. Patients may have a history of high blood pressure, vascular disease, previous strokes or heart attacks. Vascular dementia may or may not get worse with time, depending on whether the person has additional strokes. In some cases, symptoms get better with time.
Unlike those with Alzheimer's disease, people with vascular dementia often keep their personality and normal emotional responsiveness until late stages of the disease. People with vascular dementia frequently wander at night and often have other problems commonly found in people who have had a stroke, including depression and incontinence.
SOURCE: National Institute of Neurological Disorders and Stroke; Mayo Clinic