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Strokes Can Cause Memory Loss, Too

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Alzheimer’s disease is the most widely recognized form of dementia. But there’s another cause of memory loss that people should know about—but usually don’t.

Vascular cognitive impairment (VCI), which is typically caused by multiple small strokes, has been estimated to affect 1% to 4% of adults over age 65. However, because there is no agreement on the exact definition of this condition, the actual number of affected individuals is not known. Most older adults with vascular risk factors—such as high blood pressure (hypertension) and diabetes—may have varying levels of VCI.

BLOOD VESSELS AND YOUR BRAIN

The brain requires a hefty amount of blood—about 20% of the heart’s output—to function normally. Even a slight reduction in circulation—such as that caused by small strokes—can result in symptoms, including slowed thinking, that can mimic Alzheimer’s disease.

While genetics can play a role in Alzheimer’s disease, VCI is widely recognized as the most preventable form of dementia. Even if you’ve begun to suffer early signs of this form of cognitive impairment (see symptoms below), you may be able to avoid the devastating effects of full-blown dementia.

HIDDEN BLOCKAGES

Most people imagine stroke as a life-threatening event that causes dramatic symptoms. This is true of major strokes. It is not the case with mini-strokes, also known as transient ischemic attacks (TIAs).

When Johns Hopkins researchers looked for evidence of microscopic strokes—areas of brain damage that are too small to be visible on a magnetic resonance imaging (MRI) scan—they found that such strokes are extremely common. Millions of Americans with normal cognition, including healthy adults, have probably experienced one or more of these minor mini-strokes.

What happens: Small, transitory blood clots can momentarily prevent circulation to small areas of the brain. Or vascular hypertrophy, an abnormal growth of cells inside blood vessels, may impede normal circulation. In either case, certain parts of the brain receive insufficient blood and oxygen. The damaged areas can be much smaller than a grain of rice.

Symptoms—assuming that there are noticeable symptoms—tend to be minor. People who have experienced multiple mini-strokes that affect larger or more diverse areas of the brain are those most likely to develop dementia, but it might take years or even decades before the problem is severe enough to be diagnosed. Symptoms to watch for…

  • Specific symptoms of VCI depend on the part of the brain affected. Patients who have suffered multiple mini-strokes may walk or think more slowly than they did before. Some have trouble following directions. Others may feel apathetic or confused.
  • Some mini-strokes, however, affect only the part of the brain involved in decision-making and judgment. The changes might be so subtle that a patient isn’t aware of them—at least, until subsequent mini-strokes affect larger or different areas of the brain.

GETTING THE RIGHT DIAGNOSIS

People who exhibit marked cognitive changes usually will be given an MRI or computed tomography (CT) scan. These tests sometimes reveal white, cloudy areas in the brain (infarcts) that have suffered damage from impaired circulation due to mini-strokes.

Often, however, the mini-strokes are too small to be detected. In these cases, patients may be incorrectly diagnosed with Alzheimer’s disease. (The abnormal proteins that are characteristic of Alzheimer’s cannot be detected by standard imaging tests.)

The distinction is important. There is no cure for Alzheimer’s disease. In patients with VCI, there are a number of ways to stop the disease’s progression and maintain long-term cognitive health.

BETTER VASCULAR HEALTH

Brain damage that’s caused by mini-strokes can’t be reversed. Medication—including cholinesterase inhibitors, such as donepezil (Aricept)—may modestly reduce some symptoms in patients with dementia but cannot cure it.

Preventive strategies, however, can be very effective in people with VCI alone. Most important…

Don’t let high blood pressure shrink your brain. Chronic hypertension is one of the main causes of dementia because the vascular trauma is constant. People with uncontrolled hypertension actually have smaller brains because of impaired circulation. Their risk of developing dementia is two to three times higher than that of people with normal blood pressure.

My advice: Blood pressure should be no higher than 120/80 mm Hg—and 115/75 mm Hg is better. Most people can achieve good blood pressure control with regular exercise and weight loss, and by limiting sodium and, when necessary, taking one or more blood pressure–lowering drugs, such as diuretics, beta-blockers or ACE inhibitors.

Avoid the other “D” word. By itself, diabetes can double the risk for dementia. The actual risk tends to be higher because many people with diabetes are obese, which is also a dementia risk factor.

Important research: One study found that patients with multiple risk factors, including diabetes and obesity, were up to 16 times more likely to develop dementia than those without these risk factors.

My advice: By adopting strategies that prevent hypertension, including weight loss and regular exercise, you’ll also help stabilize your blood sugar—important for preventing or controlling the health complications associated with diabetes.

Keep an eye on your waist. Obesity increases the risk for hypertension and diabetes and has been associated with damage to the hippocampus (the brain’s main memory center). Obese patients also have a much higher risk for obstructive sleep apnea, interruptions in breathing during sleep that can increase brain shrinkage (atrophy) by up to 18%.

My advice: Measure your waist. For optimal health, the size of your waist should be no more than half of your height. Someone who’s 68 inches tall, for example, should have a waist measurement of 34 inches or less.

If you drink, keep it light. People who drink in moderation (no more than two drinks daily for men or one for women) tend to have higher HDL, so-called “good,” cholesterol…less risk for blood clots…and a lower risk for stroke and dementia.

My advice: If you already drink alcohol, be sure that you don’t exceed the amounts described above. Drinking too much alcohol increases brain atrophy.

Get the right cholesterol-lowering drug. People with high cholesterol are more likely to develop atherosclerosis (fatty buildup in the arteries) and suffer a mini-stroke or stroke than those with normal cholesterol levels.

My advice: Talk to your doctor about statins, such as atorvastatin (Lipitor) and simvastatin (Zocor). These drugs not only reduce cholesterol but also may fight blood-vessel inflammation. Other cholesterol-lowering drugs—such as resins, which bind in the intestines with bile acids that contain cholesterol and are then eliminated in the stool—don’t provide this dual benefit.

Ask your doctor for a vitamin B-12 test. If your blood level is low, you may benefit from B-12 supplements or injections.

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Source: Majid Fotuhi, MD, PhD, a neurologist and medical director at NeuroGrow Brain Fitness Center in McLean, Virginia. He is author of The Memory Cure and Boost Your Brain. Date: May 16, 2017 Publication: Bottom Line Health
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