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Scientists around the world are learning more about changes in the brain that can lead to dementia, including Alzheimer’s disease. There are drugs that may improve the quality of life for people living with dementia, but there is no cure. Research may someday lead to new treatments to prevent or slow dementia. In the meantime, though, evidence suggests that the vascular damage that occurs in the brains of most people with dementia may be preventable. Vascular damage to the brain usually occurs gradually, for example due to the cumulative impact of multiple small or “mini” strokes, that occur unnoticed as we age. High blood pressure is the main culprit. Over time, high blood pressure weakens the brain’s blood vessels, and may bring on processes in your body such as strokes that can cause or worsen dementia. The good news is that we know a lot about what causes high blood pressure, and there are many safe, effective ways to get it under control.

What is Dementia?

Most of us know someone — a friend, a family member — living with dementia. Many people think of it as a single disease with the main symptom being memory loss. However, a number of different diseases can result in dementia, and the word itself describes a group of symptoms that negatively affect how the brain works. Symptoms include memory loss, as well as changes in mental abilities such as reasoning and judgment, in a way that can make it difficult to perform any number of once routine daily activities. Some people with dementia can experience changes in personality while others may become agitated, delusional, or have slowed thinking. Memory loss alone does not mean someone has dementia.

Memory Loss

Problem Solving

Personality Change

Slowed Thinking

Forms of Dementia

While Alzheimer’s disease is the most common dementia diagnosis, the brain changes traditionally associated with Alzheimer’s disease, beta-amyloid plaques and tau tangles, are rarely the only disease processes in people with dementia. Autopsy studies have shown that most patients who die with dementia have a combination of these Alzheimer’s markers along with brain injury due to vascular disease such as silent strokes. Further, there are several other abnormal proteins that can accumulate in the brains of people with dementia. All of this pathological complexity means that a spectrum of dementia forms exists, depending on which combination of these changes are happening in an individual’s brain. Experts now believe that the processes that give rise to vascular disease in the brain and these several forms of dementia often converge, dramatically increasing the likelihood and severity of dementia more than either condition alone.

Learn more about dementia at our NINDS Dementia Information Page. There, you can also find out about other organizations that provide helpful information.

The Link Between Stroke and Dementia

Strokes are one type of vascular disease that can cause a host of cognitive disabilities, including effects on memory, speech and language, and everyday problem solving. Individuals who have had a stroke are anywhere between 2 times to 8 times more likely to later develop dementia, depending on the severity and number of strokes experienced. But even without suffering an obvious stroke, individuals at risk for stroke may experience cognitive impairment as their blood vessels deteriorate. These brain changes increase one’s risk of later developing age-related cognitive decline and dementia.

Learn more about some of the research on high blood pressure, dementia, and stroke.

How High Blood Pressure Is Linked to Dementia

The heart and brain are the two hardest working organs in your body. They are so closely linked that the conditions that put one at risk of poor health can affect the other. Here are the important ways they are connected:

The heart supplies blood to all the parts of your body, including the brain.

When blood enters the brain, a complicated network of blood vessels distributes oxygen and nutrients to billions of brain cells. Brain health is linked, in part, to the health of blood vessels that supply the brain.

High blood pressure causes these delicate blood vessels to become scarred, narrowed, and diseased. This can affect the bloodstream’s ability to provide nerve cells with the oxygen and nutrients they need to function and survive.

Over time, damage to the brain’s blood vessels may lead to cognitive impairment and vascular dementia. This damage may begin in middle age, years before people start to have memory and other problems related to dementia.

High blood pressure can also lead to “diffuse white matter disease” and silent strokes, which are linked to later development of cognitive decline and vascular dementia.

High blood pressure is the most preventable cause of stroke. As many as 30 percent of stroke survivors develop post-stroke dementia. Scientists believe that the same risk factors that lead to stroke can also lead to cognitive impairment and vascular dementia.

More Risks to Your Brain’s Health

Stroke occurs when blood circulation to the brain fails either because blood flow is blocked or because a blood vessel ruptures and bleeds into surrounding brain tissue. Brain cells can die as a result and the consequences can be mild to severe depending on the size and location of the stroke.

Transient ischemic attack (TIA), sometimes called a mini-stroke, starts just like a stroke but then resolves leaving no noticeable symptoms or deficits. The occurrence of a TIA is a warning that the person is at risk for a more serious and debilitating stroke.

Silent strokes (or infarcts) show up as multiple areas of ischemic tissue damage (which occurs when an artery to the brain is blocked) on MRI scans or in brains examined after death. In contrast to strokes that cause immediate and obvious consequences, silent strokes go unnoticed because they are so small, or because they occur in areas that are not directly responsible for movement, speech, vision, or other critical functions.

Diffuse white matter disease is a change in brain structure that can be seen on MRI scans in the majority of older people, affecting as many as 80 percent of those over age 80. Research has demonstrated an association between these white matter lesions and blood pressure levels, with higher blood pressure over time being linked to more extensive areas of white matter damage. Some studies also suggest a link between severe white matter lesions and diminished performance on tests of cognitive function.

Heart disease is a disorder of the blood vessels of the heart that can lead to a heart attack. A heart attack happens when an artery becomes blocked, preventing oxygen and nutrients from getting to the heart.

“People need to think about how they can decrease their chances of developing dementia in later life. With what we now know, controlling hypertension is at the top of the list.”

Walter Koroshetz, M.D., Director of NIH's National Institute of Neurological Disorders and Stroke

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