The ability to balance on one leg for 20 seconds is a sign of a healthy brain

20 seconds.
20 seconds.
Image: Reuters/Charles Platiau
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A lot has been written about the debilitating and potentially deadly after-effects of stroke. That’s why many of us try (or at least attempt) to steer clear of junk food, exercise regularly, keep an eye on the scales, and sit on the yoga mat once in a while. But what about standing on one leg for 20 seconds?

Some of us have bookmarked pages from health websites that list the common warning signs of an impending stroke. Now here’s another piece of assuring news: Scientists have devised a simple test that can gauge the risk of a person suffering a stroke.

The good news is that you don’t have to trudge to the doctor’s office to undergo the test. The one-leg balancing test, by a team of Japanese researchers, is believed to be an effective indicator of the probability of stroke in a person.

Try standing on one leg for 20 seconds

The one-leg balancing test is based on the premise that the capability to balance oneself on one leg is a critical indicator of the functional ability of the brain. A person should be able to maintain this balance for more than 20 seconds. Any duration less than this calls for a medical check-up unless this incapability can be explained by another physical reason.

Kyoto University researchers led by Yasuharu Tabara enrolled about 1,300 participants—both men and women, aged around 67 years—and asked them to stand on one leg, keep their eyes open, and maintain balance for about 20 seconds. They were then tested for brain health. The results of the tests, published Dec 2014 by the American Heart Association, are startling.

More than 30% of the subjects who had trouble balancing themselves for this length of time were found to have cerebral small vessel disease, minute hemorrhages, or both. Cerebral small vessel disease develops when the capillaries in the brain thicken and impede the smooth flow of blood. The capillaries may even bleed and cause hemorrhages in the brain that can lead to strokes. On MRI scans, cerebral small vessel disease is manifested as lacunar infarction, which is a condition when inadequate blood supply causes a tissue to die or start to die, and white matter lesions.

What makes the one-leg balancing test valid?

The scientific and medical community does not doubt the validity of the one-leg balancing test.

Firstly, the test results have been adjusted for factors such as family history of cardiovascular disease in the subjects, previous instances of cardiac ailments, and hypertension that can affect the risk incidence of strokes. So the findings of the test can be strongly correlated to the performance of the subjects on the one-leg balancing test.

Secondly, several studies have conclusively proved the association between cerebral small vessel disease and an increased risk of strokes. They have demonstrated that cerebral small vessel disease increases the risk of some people suffering a stroke whether or not they have a history of cerebrovascular disease.

There have also been several studies that have associated postural stability and being able to maintain proper gait to brain health. The results from these studies lend credibility to the one-leg balancing test as an indicator of possible brain damage and stroke.

According to one study, hand and leg coordination is controlled by a complex neural network. The sensory circuits that control your vision, your sense of your body’s position in space, and the optimal functionality of the vestibular system determine your ability to balance yourself. So an inability to maintain balance could indicate damage in the neural circuitry and warrants medical attention.

Balance dysfunction is common after a stroke, and the most severe strokes tend to cause the most severe physical disabilities. On the other hand, research studies indicate that stroke leads to permanent brain damage that, in turn, may cause long-term disability like inability to achieve and/or maintain balance. So if you connect the dots, it seems likely that balance impairment is indicative of brain damage that, in turn, can increase the risk of strokes.

Another study suggests a strong association between lesions in a particular region of the brain resulting from strokes and gait dysfunction. During this study on chronic stroke patients, scientists discovered that subjects who exhibited asymmetrical gait were 60-80% more likely to have suffered some damage to the posterolateral putamen region of their brains than those who had no abnormalities in their postures.

The one-leg balancing test administered as part of the Japanese study also suggests an association between advanced age and postural instability. Small vessel diseases tend to affect people aged 60 years and more, and in this light, this association seems valid.

According to the findings of the above study, those who could balance themselves for the shortest time also performed the poorest on mental cognition tests. A study performed in 2008 demonstrated that cerebral small vessel disease is associated with cognitive decline. A progression of the disease is associated with greater cognitive decline and the development of typical age-related conditions like dementia, Alzheimer’s disease, and Parkinson’s disease. This indicates that cognitive performance is also a critical indicator of the risk of stroke in people, especially those who struggle to balance themselves on one leg for a minimum of 20 seconds.

Implications of the one-leg balancing test

The implications of the one-leg balancing test should not only interest individuals who want to know if they are at greater risk of suffering strokes. Physicians should make high-risk patients—those with a family history of cardiac ailments and/or are suffering from diseases like hypertension and diabetes—undergo this test or enlighten them on it. Doctors should also take care to test the cognitive functionality of their patients to determine the risk of strokes.

Although there have been scientific studies linking postural instability to possible brain abnormalities, the one-leg balancing test is the first of its kind that has added a definite time frame to the test. This has increased the accuracy of the test. This gives hope to countless people and a chance to thwart a stroke that can bring their lives to a standstill.