Vascular Dementia is one of the second most common types of dementia, along with Lewy Body Dementia. Formerly called "multi-infarct dementia," this disease was once thought to only be caused by series of small strokes. However, the name was later changed to "Vascular Dementia" to reflect the wide array of conditions that can lead to this form of dementia. Vascular Dementia often occurs at the same time as Alzheimer's Disease, resulting in a condition called "Mixed Dementia".
Prevalence of Vascular Dementia
Vascular Dementia accounts for 20-30% of all dementia cases. Research estimates suggest that between 1% and 4% of people over the age of 65 have this disease. The risk of developing this form of dementia increases dramatically with age.
Causes of Vascular Dementia
Vascular Dementia results from impaired blood flow to the brain. This can occur either from a narrowing or a complete blockage of blood vessels in the brain, which deprives neurons (cells in the brain and spinal cord) from obtaining the nutrients and oxygen they need to function properly.
Often, Vascular Dementia results from several small strokes - also called infarcts or transient ischemic attacks (TIAs) - that occur over time. Strokes are disruptions in the blood supply to the brain (for more information on strokes, click here to visit our related topic center). Vascular Dementia that is caused by TIAs develops gradually, because several TIAs can occur before any dementia-like symptoms become apparent.
Vascular Dementia can also occur after a single major stroke, which is sometimes referred to as "post-stroke dementia." Not all strokes lead to dementia, but up to one third of those who have a stroke will develop dementia within six months. Conditions that do not completely block blood vessels, but simply narrow them (e.g., diabetes and high blood pressure) can also lead to vascular dementia.
Risk Factors for Vascular Dementia
Individuals who develop Vascular Dementia often have a history of one or more of the following conditions: heart attack, previous stroke, TIAs, extremely high or low blood pressure, diabetes, brain hemorrhage, blood vessel damage from a disorder such as lupus (a disease caused by a malfunctioning immune system), or high cholesterol.
If a person has a history of TIAs, the risk of developing Vascular Dementia increases with the number of TIAs experienced over time. People that have experienced a stroke which affected their language abilities are also at an increased risk of developing Vascular Dementia. High blood pressure induces extra tension in the blood vessels throughout the body - including in the brain - increasing one's risk for this form of dementia. Finally, those with diabetes are at a higher risk for Vascular Dementia because high glucose levels damage blood vessels, increasing the risk for stroke and other problems that impair blood flow to the brain.
Symptoms of Vascular Dementia
The DSM-IV outlines specific criteria for the diagnosis of Vascular Dementia. First, the individual must display multiple cognitive deficits, one of which must be memory impairment. In addition, the person must have one or more of the following symptoms:
- Aphasia - A deterioration of language abilities
- Apraxia - Difficulty executing motor activities
- Agnosia - An impaired ability to recognize or identify objects
- Problems with executive functioning (the ability to plan, make decisions, and carry out daily tasks)
In order to meet the DSM criteria for vascular dementia, a person's cognitive deficits must cause significant impairment in occupational and/or social functioning. In other words, the cognitive impairment must affect one's ability to hold a job or volunteer position, carry out domestic responsibilities, and/or maintain social relationships. The deficits must also represent a significant decline from the person's previous level of functioning.
Part of the diagnosis of Vascular Dementia involves examining a person for a pattern of problems that health care professionals call "focal neurological symptoms" (e.g., exaggerated or overly strong reflexes; walking problems; and/or weakness in the arm, legs, hands, and feet), which are signs that vascular disease is occurring.
A diagnosing clinician will also make sure that the person's deficits do not occur only during an episode of delirium (discussed later in this paper), in which case, the more appropriate diagnosis would be delirium. While not necessary (according to the DSM-IV) for the diagnosis of Vascular Dementia, some people also experience other symptoms as part of the disorder, such as delusions (fixed, false beliefs), confusion, agitation, urinary problems, and/or depressed mood.