Balance on one leg and your stroke risk are linked - Web MD. Individuals who could not balance on one leg for more than 20 seconds were association with cerebral small vessel disease. It was also independently linked to lower cognitive scores. The more damage individuals had the shorter the amount of time they were able to stand. Doctors are recommending this as a quick screening test for the risk of stroke.
A more advanced version of the test would involve trying to do this with closed eyes. I needed to do this as part of physical therapy and found it to be difficult. I'd recommend keeping the area around the test area soft and safe.
