Swank Center for Memory Care and Geriatric Consultation, ChristianaCare
For centuries, the link between bodily health and blood circulation has been recognized. Brain health, the basis of cognitive functioning, is no exception to this rule. The brain is a greedy consumer of the oxygen and nutrients that arterial blood brings to the entire body. When these vital supplies are compromised, the brain is harmed. Memory and other cognitive functions, too, show the effects of this deprivation.
“A man is as old as his arteries.” Thomas Sydenham (1624-1689)
Mrs. Watson* came to see me at her husband’s urging to discuss concerns about her memory. Her husband was very much aware of the relationship between cardiovascular health and overall quality of life. Since his own heart attack at age 70, he had paid much more attention to diet and exercise than ever before. The results were apparent; he was bright-eyed, energetic, and spoke to me in a very organized way.
Mrs. Watson, despite his encouragement, had been less attentive to her health. During the past year, her husband had grown more and more concerned about this. He saw that she was having greater trouble managing her responsibilities and relationships than would be expected for a 72-year-old woman. She was much slower in getting things done. Getting started, and acting in an organized way, was much more difficult. She often struggled to remember names and other important things.
Usually the details would come back to her once someone gave her a reminder. She continued to drive, but avoided the highways. She had become a more cautious driver, she said, and she mentioned that she had become increasingly dependent on her GPS even when driving somewhere familiar.
The explanation for her memory and other difficulties seemed clearer once we discussed her medical health. She was under the care of a cardiologist for her high blood pressure and high cholesterol. Her diabetes was treated by her primary care clinician, and she had been a heavy smoker from her 20s until her 60s.
The vascular system is the body's network of blood vessels. “Vascular risk factors” such as blood pressure that is too high or too low, diabetes, hyperlipidemia (increased levels of lipids in the blood, including cholesterol and triglycerides), smoking, and atrial fibrillation (an irregular and rapid heartbeat) can take a serious toll on the brain.
Mrs. Watson’s physicians had checked the flow in her carotid arteries with ultrasound examination and found them to be narrower than expected. Her brain MRI showed no strokes, but the hazy clouding called “white matter hyperintensities” appeared prominently throughout the areas beneath her brain’s surface. Her evaluation also included a search for other medical causes of cognitive decline including medication effects, excessive use of alcohol, endocrine disorders, infections, sleep disorders, and depression. None of these were present. Her diagnosis, in my opinion, was vascular cognitive impairment. Because she continued to function independently, needing only a little support for more complex activities, she was said to have vascular mild cognitive impairment.
Like Alzheimer's, vascular cognitive impairment is a spectrum of diseases that includes both milder and more severe degrees of impairment. We talk about vascular cognitive impairment, not just vascular dementia, in order to include the earlier stages of vascular disease’s effects on cognition. Just as mild cognitive disorder often precedes full blown Alzheimer’s dementia, there is a vascular mild cognitive impairment that precedes vascular dementia. Vascular dementia, like Alzheimer’s disease, is usually the end stage of a long disease process. There are also, as in Alzheimer’s disease, some early onset types of vascular cognitive impairment and some people have a genetic predisposition to develop vascular dementia.
Vascular dementia is caused by damage to brain cells deprived of blood flow and life-sustaining oxygen and nutrients due to reduced circulation or blockage of the brain’s blood vessels. The subsequent brain damage results in cognition and behavior changes.
These days, we focus heavily on the importance of Alzheimer’s disease, and that makes sense because Alzheimer’s is the most common form of dementia. Vascular dementia, though, is thought by some authorities to be the second most frequent dementia. To make matters worse, vascular dementia often accompanies Alzheimer’s disease. Vascular dementia is a destination that can be reached by more than one path.
Significant strokes, and especially strokes that are strategically located in vital brain areas, can knock out specific mental functions. A strategically located stroke, such as one in the thalamus, can produce a dementia that comes on abruptly.
Tiny widespread strokes (lacunar infarcts), too, can lead to dementia by nibbling away at the brain until a person’s ability to compensate for the lost brain cells is overwhelmed. In this situation, dementia appears to have developed more slowly.
Finally, another dementia of gradual onset occurs when chronic deprivation of blood flow to the brain, not severe enough to cause a stroke, damages the pathways through the brain’s white matter that connect and coordinate brain areas. White matter disease that affects communication with the frontal lobes, for example, may contribute to the typical memory problem in vascular dementia, which is a disruption of memory retrieval. It’s possible, too, that white matter disease contributes to the typical changes in personality and mood that are common in vascular dementia. This white matter disease causes destruction on a smaller scale than strokes, but the accumulated damage can be seen in MRIs.
Lifestyle factors, though, play a critical role in the development and progression of vascular cognitive impairment. High blood pressure, high cholesterol, obesity, diabetes, and smoking in mid-life will significantly increase the risk for later dementia. The importance of these factors, fortunately, points toward reasonable steps that we can take in order to reduce risk.
Medical treatments such as blood pressure medications, statins (cholesterol-lowering drugs), hypoglycemic agents and insulin are all valuable tools for limiting the consequences of established medical disorders. The symptom-reducing medications used in Alzheimer’s disease are also used in vascular dementia—but it’s even more important to reduce the risk of vascular cognitive impairment by preventing the development of the known risk factors. Weight control, appropriate physical activity, and a healthy diet are all powerful contributors to better health in later years. Making sure to include even one daily serving of fruits and vegetables in your diet will significantly lower your stroke risk. And it is never too late to benefit from quitting smoking.
Read a related article on decreasing your risk of developing Alzheimer's disease.
Even though Mrs. Watson had vascular mild cognitive impairment by the time she came to see me, there was much that could be done to help her. It may be impossible to prevent her further decline to vascular dementia, but it’s not too late for her to address her medical conditions, exercise appropriately, and watch her diet and weight. With these lifestyle changes, she may be able to optimize her physical and cognitive health and prolong her quality of life.
*To protect anonymity and to illustrate features of vascular cognitive impairment, Mrs. Watson’s story is a composite of symptoms from various patients.
Sources:
Therapy and Imaging
General Vascular Contributions to Alzheimer’s
Clotting
James Ellison, MD received his medical degree from UCSF in 1978 and trained in psychiatry at the Massachusetts General Hospital (1979-1982).
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