Comparison of the static and dynamic balance performance in young, middle-aged, and elderly healthy people

Background: Body sway increases with age. The purpose of this study was to obtain baseline data and the characteristics of balance performance in different age groups for balance strategy management. Methods: Healthy individuals (n = 107) were divided into young, middle-aged, and elderly groups, and assessed by computerized dynamic posturography (CDP) on a Smart Balance Master. The 6 subtests in the sensory organization tests (SOT) for the CDP were as follows: subtest 1, eyes open, fixed support platform; subtest 2, eyes closed, fixed platform; subtest 3, eyes open, fixed platform; subtest 4, eyes open, swaying platform; subtest 5, eyes closed, swaying platform; subtest 6, swaying visual surround, swaying platform. Motor balance control tests included the limit of stability (LOS) test at 75% of LOS in 8 directions and the left/right and forward/backward rhythmic weight shift (RWS) test. Results: In the SOT, the elderly group demonstrated significantly lower average stability and maximal stability scores in subtests 4-6. This group also demonstrated a relatively lower average percentage of ankle strategy in subtests 4-6. In the motor control tests, the elderly group demonstrated a significantly higher overall reactive time and lower overall directional control in the LOS test, lower on-axis velocity during the forward/backward and left/right motor control test and a lower average percentage of forward/backward directional control in the RWS test. Conclusion: The elderly had a higher degree of postural imbalance and used hip strategy to a greater extent to maintain their balance, especially when standing on a swaying support surface in the absence of visual surround or with conflicted visual surround. The elderly required a longer reaction time and demonstrated lower directional control in balance performance.