Non-linear dynamics of human locomotion: effects of rhythmic auditory cueing on local dynamic stability
Non-linear dynamics of human locomotion: effects of rhythmic auditory cueing on local dynamic stability
复制标题
人体运动的非线性动力学：节奏听觉提示对局部动态稳定性的影响
作者：
P. Terrier;O. Deriaz
已经观察到步态参数[步幅长度（SL）、步幅时间（ST）和步幅速度（SS）]的时间序列表现出长期持续性和分形性质。同步步骤与有节奏的听觉刺激修改的持续波动模式反持久性。另一种非线性方法估计步态控制对小扰动的弹性程度，即，局部动态稳定性（LDS）。该方法利用最大李雅普诺夫指数，估计嵌入在重构的状态空间（吸引子）的非线性系统在无穷小扰动后发散的速度。我们建议使用仪器跑步机，同时测量基本步态参数（SL，ST和SS的时间序列，可以评估连续步幅之间的统计持久性），和压力中心的轨迹（可以估计LDS）。在20名健康受试者中，对LDS和统计持久性的节律性听觉提示（RAC）的反应进行了比较[用去趋势波动分析（DFA）评估]。通过分析发散曲线，我们观察到长期LDS（计算为重建吸引子中最近邻下游第4步和第10步之间的平均对数发散率的倒数）强烈增强（相对变化+73%）。这可能是一个更受抑制的动态的迹象。短期LDS的变化（一个步骤上的分歧）较小（+3%）。DFA结果（标度指数）证实了ST，SL和SS的抗持久性模式。长期LDS（而不是短期LDS）和标度指数之间表现出显着的相关性（r = 0.7）。这两种现象可能是由于RAC所需的更有意识/自愿的步态控制。我们建议，LDS和统计持久性应用于评估神经步态障碍患者的暗示治疗的有效性。
It has been observed that times series of gait parameters [stride length (SL), stride time (ST), and stride speed (SS)], exhibit long-term persistence and fractal-like properties. Synchronizing steps with rhythmic auditory stimuli modifies the persistent fluctuation pattern to anti-persistence. Another non-linear method estimates the degree of resilience of gait control to small perturbations, i.e., the local dynamic stability (LDS). The method makes use of the maximal Lyapunov exponent, which estimates how fast a non-linear system embedded in a reconstructed state space (attractor) diverges after an infinitesimal perturbation. We propose to use an instrumented treadmill to simultaneously measure basic gait parameters (time series of SL, ST, and SS from which the statistical persistence among consecutive strides can be assessed), and the trajectory of the center of pressure (from which the LDS can be estimated). In 20 healthy participants, the response to rhythmic auditory cueing (RAC) of LDS and of statistical persistence [assessed with detrended fluctuation analysis (DFA)] was compared. By analyzing the divergence curves, we observed that long-term LDS (computed as the reverse of the average logarithmic rate of divergence between the 4th and the 10th strides downstream from nearest neighbors in the reconstructed attractor) was strongly enhanced (relative change +73%). That is likely the indication of a more dampened dynamics. The change in short-term LDS (divergence over one step) was smaller (+3%). DFA results (scaling exponents) confirmed an anti-persistent pattern in ST, SL, and SS. Long-term LDS (but not short-term LDS) and scaling exponents exhibited a significant correlation between them (r = 0.7). Both phenomena probably result from the more conscious/voluntary gait control that is required by RAC. We suggest that LDS and statistical persistence should be used to evaluate the efficiency of cueing therapy in patients with neurological gait disorders.
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影响因子：
2.4
作者：
Dingwell, Jonathan B.;Cusumano, Joseph P.
通讯作者：
Cusumano, Joseph P.
影响因子：
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影响因子：
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作者：
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