The Effect of Age on Balancing Behavior: Complexity Analysis of Mediolateral Force Trajectories
Objective: We quantified, via complexity analysis, the postural stability of healthy people from a wide age range. Approach: Thirty-five healthy people aged 18-72 performed three tasks while balancing on one foot on a force plate: standard balancing task, mental task (balancing while answering basic arithmetic questions), and knot-tying task (balancing while tying two knots in a piece of ribbon). Mediolateral force trajectories were analyzed to determine control strategy via Hurst exponents, Lyapunov exponents, Kolmogorov complexity, root mean square, and phase-space plots. Main results: We found increased pattern repetition in balancing with increased age, as evidenced by the emergence of a double attractor pattern in phase-space plots and the increase of Hurst exponents with age from approximately 0.3 to 0.8. Significance: As people age, they tend to develop strong feed-forward control strategies for balancing, and lose the complexity of micro movements intrinsic to young age. There is an open-loop control strategy for balancing that emerges in older adulthood, and there are attractors inherent to balancing which begin to develop in middle age.
Hilbun, A. L.; and Karsai, I.. 2018. The Effect of Age on Balancing Behavior: Complexity Analysis of Mediolateral Force Trajectories. Physiological Measurement. Vol.39(1). https://doi.org/10.1088/1361-6579/aa9d0b PMID: 29176038 ISSN: 0967-3334