A Little-Known Cause of Memory Problems
The tiny blood vessels that supply our brains with nutrients and oxygen become vulnerable to damage as we age. This damage, called cerebral small vessel disease, increases the risk of stroke and cognitive decline (including vascular dementia, the second most common form of dementia after Alzheimer's disease), especially when it's coupled with conditions like high blood pressure or diabetes. But its effects can also be more subtle, causing walking and balance problems or memory lapses and a loss of focus.
Cerebral small vessel disease is one of the most common neurological disorders of aging—nearly all of us develop some form of the disease as we get older. In 1999, the Rotterdam Scan Study found that of 1,077 people ages 60–90, more than 90 percent showed evidence of cerebral small vessel disease. A more recent study, published in the October 2017 issue of Neurology, found a similar prevalence.
Researchers don't know for sure why not everyone will develop troublesome symptoms nor have to contend with cerebral small vessel disease's most serious consequences. Some people never experience any symptoms. According to a review published in July 2018 in Nature Reviews Neurology, "Clinical symptoms are often highly inconsistent in nature and severity among patients with similar degrees of [small vessel disease] on brain imaging."
Still, over time, cerebral small vessel disease can cause a variety of symptoms. Among the most common:
- Difficulty making decisions, solving problems, planning, or organizing
- Difficulty following a series of steps, such as a recipe or an instruction manual
- Slower speed of thought
- Memory lapses
- Changes in gait
- Increased falls
- Depression or mood swings
- Confusion or disorientation
- Urinary incontinence
Having one or more of these symptoms, however, does not mean you have cerebral small vessel disease. Medical problems such as a thyroid condition or a vitamin deficiency can affect mental status and result in similar symptoms, as can side effects from certain drugs.
Detecting small vessel disease
Doctors can see changes in the brain related to small vessel disease by using magnetic resonance imaging (MRI). The most common MRI finding characteristic of cerebral small vessel disease is white matter hyperintensities (WMHs). Most WMHs are associated with a series of tiny "silent strokes," which occur when a clot forms in a small artery, cutting off blood flow to a tiny region of the brain. Unlike larger strokes, these very small strokes, known as silent lacunar infarcts, don't cause noticeable symptoms, so you usually won't be aware that one has occurred. It's not until lacunar infarctions accumulate over time that they may cause symptoms such as walking and balance problems.
MRIs can also detect microbleeds and enlarged perivascular spaces, which are also associated with small vessel disease. Microbleeds are tears or ruptures in the vessel walls, which allow blood cells to leak into brain tissue. Enlarged perivascular spaces—fluid-filled areas that surround the vessels—are thought to sometimes be caused by brain shrinkage (atrophy). Both are associated with advancing age.
Who's at risk?
Along with aging, high blood pressure is considered to be the major risk factor for small vessel disease. Other risk factors for cerebral small vessel disease include atherosclerosis (hardening of the arteries), diabetes, smoking, a sedentary lifestyle, and excessive alcohol consumption.
No treatment exists that specifically targets cerebral small vessel disease. But you can protect the tiny blood vessels in your brain and lower your risk of symptomatic small vessel disease by following the same lifestyle management modifications and strategies used to protect against stroke and heart disease:
- Have your blood pressure checked regularly. If you have high blood pressure, work with your doctor to get it under control.
- If you have diabetes, follow your doctor's advice to keep your blood sugar levels well-managed.
- Keep your cholesterol levels under control. Your doctor may prescribe a statin if diet and exercise aren't enough to help.
- Follow a heart-healthy diet centered around vegetables, fruits, legumes, and whole grains.
- Find ways to be more physically active. Aerobic activities that increase heart rate and respiration can lower blood pressure and help keep blood vessels healthy.
- If you're overweight, work out a plan to lose some excess pounds.
- Drink alcohol only in moderation.
- If you smoke, talk to your doctor about approaches that can help you stop.