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What is vascular dementia?

Vascular cognitive impairment refers to cognitive problems that stem from insufficient blood flow to portions of the brain. The decrease in blood flow is often the result of atherosclerosis (the accumulation of fatty deposits on artery walls) in the blood vessels that feed the brain. The resulting interruption of blood flow in small arteries creates areas of dead tissue. These events—which are in fact tiny strokes—often go unnoticed, because each one damages just a small part of the brain and may not cause obvious cognitive impairment. But the cumulative damage can lead eventually to large areas of dead brain tissue, and symptoms such as confusion, impaired thinking, slurred speech, problems with walking and paralysis may arise. When severe, the condition is called vascular dementia.

Strokes in larger blood vessels can also cause dementia. People with vascular dementia usually have hypertension (high blood pressure), cardiovascular disease, diabetes, high cholesterol and triglycerides, or a history of stroke. The classic symptom of vascular dementia is an abrupt mental change, sometimes accompanied by paralysis or slurred speech. The mental deterioration proceeds in a "stairstep" pattern—a person suffers a sudden cognitive decline, the decline levels off, and then new strokes cause more sudden declines.

Vascular dementia, the second most common cause of dementia, accounts for slightly more than 20 percent of dementia cases. It is usually the result of damage that is done to the brain by a stroke, which happens when a blood clot or a hemorrhage cuts off the brain's blood supply.

Sometimes just a single stroke will cause the dementia. That type of case is called a single-infarct dementia. It is more common, however, for a number of small strokes to have the cumulative effect of destroying brain tissue and affecting memory, language and other cognitive functions. When this happens, it is described as multi-infarct dementia.

Dr. Stephen T. Chen, MD
Geriatric Medicine Specialist

Unlike other types of dementia—including Alzheimer's disease, frontotemporal dementia or Lewy body dementia—vascular dementia isn’t due to a problem in the brain. Instead, vascular dementia starts in the blood vessels that supply the brain with blood and oxygen. Doctors call this “ischemia.” The blood supply problem may be due to narrowing of the arteries, or sometimes there can be a bleed that disrupts blood flow and oxygen. The inadequate blood supply leads to brain cell damage or death, causing that part of the brain to no longer work properly.

Large, single strokes can affect brain function. But sometimes, small blood vessels in the brain are damaged over a longer period and may not be noticed. You may not have the same signs as what you might expect from a stroke. It may be a very, very subtle injury, or what doctors call a “subclinical” injury. There are no real symptoms, until they build up slowly over time. This sometimes lead to vascular dementia.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.