A new study by Japanese researchers has found that inability to balance on one leg for longer than 20 seconds was linked with having had minor small vessel damage or infarction in the brain, such as microbleeds and lacunar infarction, otherwise known as “silent strokes.”
Minor small vessel damage indicates that the person is at higher risk of major small vessel damage known as stroke, and dementia.
Thus, according to the researchers, the ability to stand on one leg could be a simple but effective test for the early signs of brain abnormalities caused by minor small vessel infarction that could lead to stroke and dementia.
Strokes are small blood vessel damage that interrupt blood flow to a part of the brain, while dementia, often related with small blood vessel damage, involves cognitive function decline in otherwise healthy adults.
The researchers warned that although microbleeds and “silent strokes” are small cerebrovascular events that may cause no major symptoms, they could serve warning of future serious health problems, such as a fatal stroke and dementia.
According to lead researcher Yasuharu Tabara, associate professor at the Center for Genomic Medicine at Kyoto University in Japan, “Our study found that the ability to balance on one leg is an important test for brain health.”
“Individuals showing poor balance on one leg should receive increased attention, as this may indicate an increased risk for brain disease and cognitive decline.”
The study involved 841 and 546 women and men, respectively, with an average age of 67. They were asked to try to balance or stand on one leg with their eyes open, and allowed up to 60 seconds to keep the leg raised. Each participant performed the exercise twice, and the better of the two attempts was included in the analysis.
The participants were then evaluated for levels of small vessel damage using brain magnetic resonance imaging (MRI).
The results of the analysis, published December 18, in the American Heart Association’s journal Stroke, under the title, “Association of Postural Instability With Asymptomatic Cerebrovascular Damage and Cognitive Decline,” found that 34.5 percent of participants with more than two lacunar infarction lesions experienced difficulty balancing on one leg for longer than 20 seconds.
Sixteen percent of participants with one lacunar infarction lesion and 30 percent of participants with more than two microbleed lesions also experienced difficulty balancing on one leg for more than 20 seconds.
The study also found that 15.3 percent of participants with one microbleed lesion had trouble balancing.
“One-leg standing time is a simple measure of postural instability and might be a consequence of the presence of brain abnormalities.”
The researchers found a strong correlation between age and ability to stand on one leg. They found there was a marked decrease in the ability to balance on one leg after age 60. This was attributed to the fact that the incidence of small vessel disease tends to increase with age, especially among older people with high blood pressure.
The researchers adjusted statistically for age so that they can correlate microbleeds and lacunar infarctions with postural instability independent of the age of participants. They found that regardless of age, people with minor brain blood vessel disease showed signs of postural instability and cognitive decline.
The study was unique because while previous studies had looked only at the link between postural stability and the risk of stroke and dementia, the new study was the first to look at how to use postural stability as an indicator of cerebrovascular health. The value of the test, which, effectively, is a simple low-tech way to predict whether someone has had a microbleed or “silent stroke” in the past, is that it offers a quick and easy way for clinicians to assess early signs of the risk of stroke and dementia. This allows doctors to give closer medical attention to people assessed as being at higher risk of stroke and dementia.
The implication of the study is that small blood vessel (“arteriole”) damage due to decreased elasticity, narrowing, or blockage of the tiny vessels embedded deep within the brain could be considered subclinical brain damage.
This is not the first time that studies have shown a correlation between ability to stand on one leg and risk of mortality. A previous study found that subjects who were able to stand with a leg raised and eyes closed for less than two seconds were three times more at risk of early death than those who could stand for up to ten seconds. A study by UK researchers also found that ability to stand on one leg and stand and sit on a chair 37 times in one minute was predictive of which 53-year-old was at high risk of early death due to several causes including stroke.