Clinical stabilometry standardization: Feet position in the static stabilometric assessment of postural stability

ntroduction: We address the topic of feet position during the quiet upright stance balance test over a force platform. Such position is widely discussed and three among the most accepted criteria were submitted to comparison. Materials and methods: 55 subjects devoid of any evident motor dysfunction were receiving the test in the three selected feet positions configurations: Joined Parallel [JP], 30° degrees with 5 cm heels apart [30°], Parallel Apart [PA] at about 15 cm distance from each other. Six sequences have been selected and applied in a random way to the subjects in order to avoid learning effects or fatigue bias in the test results. Results: The data have demonstrated that: 1) The Romberg quotients (the ratio between homologous parameters calculated in the Closed Eyes Test vs. the Open Eyes Test), although affected by the feet position, keep their standard meaning independently by the feet position; 2) A significantly greater variability of Sway Parameters is afforded by the Joined Parallel Feet [JP] while the Parallel Apart Feet position [PA] seems to afford the lowest sensitivity in quantifying balance performances; 3) The [30°] test seems to be the most comfortable one and therefore likely to be the most convenient for unstable or dysfunctional subjects that cannot keep the [JP] position; 4) The [PA] and the [30°]test are showing very similar results. Conclusion: We can therefore conclude that the first choice for feet positioning to perform balance tests on force platform should be towards the Joined Parallel Feet, the others, however, might represent a valid choice for impaired patients.