Assessment of balance abilities in elderly people by means of a clinical test and a low-cost force plate

Balance and mobility assessment, and the estimation of the risk of falls, represent crucial elements for supporting a healthy aging process. In this work, we evaluated the association of two approaches used to estimate standing balance and sit-to-stand abilities in community-dwelling older people. The clinical-based test was the Short Physical Performance Battery, while the laboratory-based assessments were realized by means of output measures obtained with the Wii Balance Board. The correlation between clinical scores and laboratory measures showed poor association for the standing balance test (.05<r<.37) and modest association for the sit-to-stand test (-.31<r<.73), respectively. Linear regression analysis was in agreement with these findings, and it revealed a model for standing balance that explained 14% of the association, and a model of sit-to-stand that explained 69% of the association. Discriminant function analysis showed significant classification agreement between the two approaches, but with different levels of accuracy. The rate of accuracy for the standing balance test was 63.3%, while for the sit-to-stand test the rate of accuracy was 92.2%. For both tests, these values were lower after a cross-validation procedure. The values of root mean square of the center of pressure was a significant predictor for different ability levels in the standing balance test, while the vertical component of the ground reaction force and the overshoot were the predictors for sit-to-stand ability levels. These findings seem to support the feasibility of using the Wii Balance Board for the assessment of balance and sit-to-stand abilities in elderly people. Therefore, medical practitioners could use this device with the clinical test for obtaining more useful information for their analysis