Usually, the symptoms of a major stroke are pretty unmistakable: sudden numbness, tingling or weakness on one side of the body; sudden vision changes; trouble speaking; confusion; sudden, severe headache and balance problems. Experiencing these symptoms always warrants an immediate trip to the emergency room, as faster treatment often leads to better outcomes and less permanent effects.
The two main types of strokes are ischemic and hemorrhagic. Ischemic strokes are caused by a blood clot blocking a blood vessel that feeds the brain. Without a steady supply of blood, that area of the brain malfunctions and/or dies. With hemorrhagic strokes, a burst blood vessel causes the damage to the brain. The symptoms that a patient experiences during the stroke reflect the area of the brain being affected. So, for instance, speech problems indicate that the stroke occurred in the area of the brain responsible for speech.
However, sometimes strokes occur and pass completely unnoticed. During these so-called “silent strokes,” the interruption of blood flow occurs in areas of the brain that do not control vital bodily functions such as speech or movement. For this reason, while they’re happening, silent strokes present either no symptoms or symptoms that go unnoticed or largely ignored.
Here’s the real kicker: According to research, approximately 12 million strokes occur every year, and 11 million of those are silent strokes.1 This means 11 million people are having strokes and most likely don’t even know about it!
Moreover, even though silent strokes present no major immediate symptoms, if they occur continuously over time, their effects can be cumulative, leading to memory problems and dementia,2 and a much higher risk for a major ischemic or hemorrhagic stroke.
This staggering statistic highlights the need for greater awareness of silent strokes, as was concluded in a recent research published in the journal Stroke.3
In this particular study, researchers hypothesized that some of those people who experience silent strokes are not actually asymptomatic, but rather are unaware that whatever symptoms they are experiencing are stroke-related. Other times, they simply ignore or forget the symptoms that they have during the silent stroke because the symptoms are not severe enough to cause worry.
To test their theory, researchers followed 649 patients who had MRIs between August 2010 and May 2012 as part of an ongoing dementia study at the Memory Aging and Cognition Center.
Six of the subjects showed lesions indicative of silent strokes that occurred zero to four days prior to the MRI. When questioned by researchers, three of those people recalled that they had symptoms that they dismissed. In two of the subjects, the symptoms were blamed on their dementia/cognitive impairment. And in the final patient, ataxia (the lack of coordinated muscle movements) was attributed to confusion.
Because these patients did not experience sudden, severe symptoms that indicated stroke, the symptoms they did notice were disregarded as anything significant. So, while many people who suffer from silent strokes really have no symptoms, some actually do—but they ignore them or chalk them up to aging or some other condition.
Can You Prevent Silent Strokes?
Some of the biggest risk factors that can lead to silent stroke include uncontrolled diabetes, heart disease, high blood pressure and high cholesterol. Studies also show a link between silent strokes and sleep apnea.4 So the most crucial step you can take to prevent silent strokes (and major strokes) is to get these conditions under control.
Second, recent research has indicated that engaging in moderate to heavy physical activity can prevent silent strokes.5 Of course, if you’ve been inactive for a while, be sure to talk to your doctor before starting any exercise program, particularly one that’s intense.
Finally, it goes without saying that you should pay attention to your body and not “blow off” or disregard any unusual symptoms, like unexplained dizziness, loss of muscle coordination, confusion, vision changes, etc. Doctors treat silent strokes much the same way they treat ischemic and hemorrhagic strokes. And the quicker you get treatment, the lower your chances of serious, long-term effects.
References:
- http://stroke-meeting.ahajournals.org/cgi/content/abstract/32/1/363-b.
- Vermeer SE, et al. N Engl J Med 2003;348:1215-22.
- Saini M, et al. Stroke. 2012 Nov;43(11):3102-4.
- http://newsroom.heart.org/pr/aha/sleep-apnea-linked-to-silent-strokes-221516.aspx.
- Willey JZ, et al. Neurology. 2011 Jun 14;76(24):2112-8
