The Most Common Aging Brain Problem You've Never Heard Of
It has been associated with other issues of older adults, such as dementia
(This article appeared previously on BetterHealthWhileAging.net.)
While leading a fall prevention workshop recently, I mentioned that an older person’s walking and balance problems might well be related to the presence of “small vessel ischemic changes” in the brain, which are very common in aging adults.
This led to an immediate flurry of follow-up questions. What exactly are these changes, people wanted to know. And do they happen to every older adult?
Well, they don’t happen to every older person, but they do happen to the vast majority of them. In fact, one study of older adults aged 60 to 90 found that 95 percent of them showed signs of these changes on brain MRI.
In other words, if your older parent ever gets an MRI of the head, he or she will probably show some signs of these changes.
So this is a condition that older adults and families should know about. Furthermore, these changes have been associated with problems of consequence to older adults, including:
- Cognitive decline
- Problems with walking or balance
- Vascular dementia
Cerebral Small Vessel Disease
Now, perhaps the best technical term for what I’m referring to is “cerebral small vessel disease.” But the medical community uses many other synonyms — especially in radiology reports. They include: small vessel ischemic disease, white matter disease, periventricular white matter changes, perivascular chronic ischemic white matter disease of aging, white matter hyperintensities, age-related white matter changes and leukoaraiosis.
Cerebral small vessel disease (SVD) is an umbrella term covering a variety of abnormalities related to small blood vessels in the brain. Because most brain tissue appears white on MRIs, these abnormalities were historically referred to as “white matter changes.”
Per a recent medical review article, specific examples of cerebral SVD include “lacunar infarcts” (a type of small stroke), “white matter hyperintensities” (a radiological finding) and “cerebral microbleeds” (bleeding in the brain from a very small blood vessel).
In many cases, cerebral SVD seems to be a consequence of atherosclerosis affecting the smaller blood vessels that nourish brain tissue. Just as one’s larger blood vessels in the heart or elsewhere can accumulate plaque, inflammation and chronic damage over the years, so can the smaller blood vessels.
Such chronic damage can lead the small blood vessels in the brain to become blocked (which starves brain cells of oxygen, and which we technically call ischemia), or to leak (which causes bleeding, which can damage nearby brain cells).
When little bits of brain get damaged in these ways, they can change appearance on radiological scans. So when an MRI report says “white matter changes,” this means the radiologist is seeing signs of cerebral SVD.
Such signs of SVD may be described as “mild,” “moderate,” or “severe/extensive,” depending on how widespread they are.
Symptoms of Cerebral Small Vessel Disease
The severity of symptoms tends to correspond to whether radiological imaging shows the cerebral SVD to be mild, moderate, or severe.
Many older adults with cerebral SVD will have no noticeable symptoms. This is sometimes called “silent” SVD.
But many problems have been associated with cerebral SVD, especially when it is moderate or severe. These include:
- Cognitive impairment. Several studies, such as this one, have found that cerebral SVD is correlated with worse scores on the Mini-Mental State Exam. When problems with thinking skills are associated with SVD, this can be called “vascular cognitive impairment.”
- Problems with walking and balance. White matter lesions have been repeatedly associated with gait disturbances and mobility difficulties. A 2013 study found that moderate or severe cerebral SVD was associated with a decline in gait and balance function.
- Strokes. A 2010 meta-analysis concluded that white matter hyperintensities are associated with a more than two-fold increase in the risk of stroke.
- Depression. White matter changes have been associated with a higher risk of depression in older people, and may represent a contributor to depression that is particular to having first-time depression in later life.
- Vascular dementia. Signs of cerebral SVD are associated with both having vascular dementia and eventually developing vascular dementia.
- Other dementias. Research suggests that cerebral SVD is also associated with an increased risk — or increased severity — of other forms of dementia, such as Alzheimer’s disease. Autopsy studies have confirmed that many older adults with dementia show signs of both Alzheimer’s pathology and cerebral small vessel disease.
- Transition to disability or death. In a 2009 study of 639 non-disabled older persons (mean age 74), over a three-year follow-up period, 29.5 percent of participants with severe white matter changes and 15.1 percent of participants with moderate white matter changes developed disabilities or died. In comparison, only 10.5 percent of participants with mild white matter changes transitioned to disability or death over three years. The researchers concluded that severity of cerebral SVD is an important risk factor for overall decline in older adults.
So what does this all mean, in terms of symptoms and cerebral SVD? Here’s how I would boil it down:
- Overall, older adults with any of the problems listed above have a high probability of having cerebral SVD.
- But, many older adults with cerebral SVD on MRI are asymptomatic, and do not notice any difficulties. This is especially true of those with mild cerebral SVD.
- Older adults with cerebral SVD are at increased risk of developing the problems above, often within a few years time. This is especially true of people with moderate or severe cerebral SVD.
What Causes Cerebral Small Vessel Disease?
This is a topic of intense research, and the experts in this area tend to really nerd out when discussing it. One reason it’s difficult to give an exact answer is that cerebral SVD is a broad umbrella term that encompasses many different types of problems with the brain’s small blood vessels.
Still, certain risk factors for developing cerebral SVD have been identified. Many overlap with risk factors for stroke. They include:
- Dyslipidemia (e.g. high cholesterol)
- Atrial fibrillation
- Cerebral amyloid angiopathy
How Can It Be Treated or Prevented?
Experts are still trying to figure out the answers to this question, and research into the prevention of cerebral SVD is ongoing.
Since progression of cerebral SVD seems often associated with clinical problems, experts are also trying to determine how we might prevent, or delay, the progression of SVD in older adults.
Generally, experts recommend that clinicians consider treating any underlying risk factors. In most cases, this means detecting and treating any traditional risk factors for stroke.
To date, studies of hypertension treatment to prevent the progression of white matter changes have shown mixed results. It appears that treating high blood pressure can slow the progression of brain changes in some people. But such treatment may be less effective in people who are older than 80, or who already have severe cerebral SVD.
In other words, your best bet for preventing or slowing down cerebral SVD may be to properly treat high blood pressure and other risk factors before you are 80, or otherwise have significant SVD.
Furthermore, experts don’t yet agree on how low to go when it comes to optimal blood pressure for an older person with cerebral small vessel disease. (This article explains why this has been difficult to determine.)
For now, to prevent the occurrence or progression of cerebral small vessel disease, it’s reasonable to start by observing the hypertension guidelines considered reasonable for most older adults: treat to a target of systolic blood pressure less than 150mm/Hg.
Whether to treat high blood pressure — and other cardiovascular risk factors — more aggressively should depend on an older person’s particular health circumstances. I explain a step-by-step process you can use (with links to related research) here: 6 Steps to Better High Blood Pressure Treatment for Older Adults.
Should You Request an MRI If You’re Concerned?
Not necessarily. In my opinion, older adults should only get MRIs of the brain if the following two things are true:
- They are experiencing worrisome clinical symptoms, and
- The results of the MRI are needed to decide on how to treat the person.
For most older adults, an MRI showing signs of cerebral SVD will not, in of itself, change the management of medical problems.
If you have high blood pressure, you should consider treatment. If you are having difficulties with walking or balance, signs of cerebral SVD do not rule out the possibility of other common causes of walking problems, such as medication side-effects, foot pain, neuropathy, and so forth.
What if you’re concerned about memory or thinking problems? Well, you probably will find signs of cerebral SVD on an MRI, just because this is a common finding in all older adults, and it’s especially common in people who are experiencing cognitive changes.
However, the MRI cannot tell you whether the cognitive changes you are noticing are only due to cerebral SVD, versus due to developing Alzheimer’s disease, versus due one of the many other dementia mimics. You will still need to pursue a careful evaluation for cognitive impairment. And no matter what the MRI shows, you will likely need to consider optimizing cardiovascular risk factors.
So in most cases, a brain MRI just to check for cerebral SVD is probably not a good idea.
However, if an MRI is indicated for other reasons, you may find out that an older person has mild, moderate, or severe signs of cerebral SVD. In this case, especially if the cerebral SVD is moderate or severe, you’ll want to consider taking steps to reduce stroke risk, and also to monitor for cognitive changes and increased disability.
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