Inadequate response to balance perturbations lead to posture instability in the elderly. The fall risks are increased by a reduced capacity to control the center of pressure (COP) displacement within the safety limit of the supporting base. This study developed an interactive evaluation and training platform. The system incorporated a computerized program with instantaneous force plate evaluation. Ten young subjects underwent a baseline evaluation and twenty-nine community-dwelling elderly received pre- and post-intervention testing. The ability to reach the stability limit was assessed by measuring the maximum voluntary excursion of the COP in anterior-posterior and medial-lateral directions. Functional mobility tests including Berg Balance Scale, Timed-Up-and-Go and functional reach were used as functional outcomes. The experimental group (n = 15) received a 40 min intervention three times a week for six weeks. The interactive game-based training focused on multi-directional weight shifting by tracing a COPcontrolled target to challenge an individual's stability limit. The control group (n = 14) maintained daily activities as usual. The young group revealed a superior COP displacement through active ankle control than the elderly, especially in the anterior-posterior direction. The experimental group improved their COP displacement control more in the medial-lateral direction due to the predominant side-to-side gameplay movement. The functional outcome measures were also significantly improved after training. Using the COPcontrolled game-based program, the stability limit was challenged to facilitate dynamic posture control by an incremental increase in self-initiated perturbations. The platform system could assist in transferring the immediate training effects into daily functional mobility in the elderly.
Keywords: balance; center of pressure; elderly; interactive training; limit of stability.