Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
Health Science and Wellness Research Center, National Taiwan University, Taipei, Taiwan.
J Neuroeng Rehabil. 2024 Nov 6;21(1):200. doi: 10.1186/s12984-024-01483-x.
Mild cognitive impairment (MCI) may lead to difficulty maintaining postural stability and balance during locomotion. This heightened susceptibility to falls is particularly evident during tasks such as obstacle negotiation, which demands efficient motor planning and reallocation of attentional resources. This study proposed a multi-objective optimal control (MOOC) technique to assess the changes in motor control strategies during obstacle negotiation in older people affected by amnestic MCI.
Motion data from 12 older adults with MCI and 12 controls when crossing obstacles were measured using a motion capture system, and used to obtain the control strategy of obstacle-crossing as the best compromise between the conflicting objectives of the MOOC problem, i.e., minimising mechanical energy expenditure and maximising foot-obstacle clearance. Comparisons of the weighting sets between groups and obstacle heights were performed using a two-way analysis of variance with a significance level of 0.05.
Compared to the controls, the MCI group showed significantly lower best-compromise weightings for mechanical energy expenditure but greater best-compromise weightings for both heel- and toe-obstacle clearances. This altered strategy involved a trade-off, prioritising maximising foot-obstacle clearance at the expense of increased mechanical energy expenditure. The MCI group could successfully navigate obstacles with a normal foot-obstacle clearance but at the cost of higher mechanical energy expenditure.
MCI alters the best-compromise strategy between minimising mechanical energy expenditure and maximising foot-obstacle clearances for obstacle-crossing in older people. These findings provide valuable insights into how MCI impacts motor tasks and offer potential strategies for mitigating fall risks in individuals with MCI. Moreover, this approach could serve as an assessment tool for early diagnosis and a more precise evaluation of disease progression. It may also have applications for individuals with impairments in other cognitive domains.
轻度认知障碍（MCI）可能导致在运动过程中难以维持姿势稳定性和平衡。这种对跌倒的高度敏感性在障碍物穿越等任务中尤为明显，这些任务需要有效的运动规划和注意力资源的重新分配。本研究提出了一种多目标最优控制（MOOC）技术，以评估记忆障碍型 MCI 老年人在障碍物穿越任务中运动控制策略的变化。
使用运动捕捉系统测量了 12 名 MCI 老年人和 12 名对照者穿越障碍物时的运动数据，并用于获得障碍物穿越的控制策略，作为 MOOC 问题中冲突目标之间的最佳妥协，即最小化机械能消耗和最大化足-障碍物间隙。使用双因素方差分析对组间和障碍物高度的加权集进行比较，显著性水平为 0.05。
与对照组相比，MCI 组在机械能消耗方面的最佳妥协权重明显较低，但在脚跟和脚趾障碍物间隙方面的最佳妥协权重较高。这种改变的策略涉及一种权衡，优先考虑最大化足-障碍物间隙，而牺牲增加的机械能消耗。MCI 组可以成功穿越障碍物，保持正常的足-障碍物间隙，但代价是更高的机械能消耗。
MCI 改变了老年人障碍物穿越时最小化机械能消耗和最大化足-障碍物间隙的最佳妥协策略。这些发现提供了关于 MCI 如何影响运动任务的有价值的见解，并为减轻 MCI 个体的跌倒风险提供了潜在的策略。此外，这种方法可以作为早期诊断的评估工具，以及更精确地评估疾病进展。它也可能适用于其他认知领域受损的个体。
