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首页> 外文期刊>Journal of Biomechanics >Spatial resolution of spontaneous accelerations in reaching tasks.
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Spatial resolution of spontaneous accelerations in reaching tasks.

机译：完成任务时自发加速度的空间分辨率。

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Reaching tasks are considered well-executed if they appear "smooth," a quality that is typically quantified by its opposite, jerk, the rate of change of acceleration. While jerk is a theoretically sound measure, its application to spastic individuals sometimes yields counter-intuitive results, and does not reveal motor impairment across the workspace. To more generally quantify spontaneous accelerative transients (SATs) within a movement, a pseudo-wavelet transform was devised that iteratively compared angular trajectories to a series of straight-line approximants. Cumulative linear fit errors were expressed in terms of flexion angle, yielding an SAT map of the entire motion. To compare SAT maps with traditional smoothness measures, two scalar indices were extracted from them: residual excursion deviation (RED), representing the integral over Deltatheta and the ratio of peak error to mean error (PEME) on the map. Fifteen subjects, including five subjects with chronic stroke performed elbow flexions throughout their entire ranges of motion, Deltatheta, at a comfortable pace with their arms supported in the transverse plane. Maps revealed that stroke subjects were significantly less coordinated than controls, as measured both by RED: 8.0+/-2.9 x 10(-3) versus 3.1+/-0.8 x 10(-3) and PEME: 6.6+/-0.9 versus 12.1+/-1.9, both P<0.001. Comparable jerk metrics, including integrated average jerk, did not report a significant performance deficit at the P<0.05 level. Map metrics for all subjects were independent of average velocity (correlation with theta : rho0.31), but jerk-based metrics for stroke subjects were spuriously co-variant with velocity rho=0.85, which may relate to the significantly higher mean arrest period ratio in stroke subjects (0.26+/-0.19 versus 0.09+/-0.08, P<0.001). We conclude that SAT maps provide reliable information on regional movement impairments at a wide range of proficiency levels.
机译：如果到达任务看起来“平稳”，则认为该任务执行良好，该质量通常由相反的，加速的变化率来衡量。虽然从理论上讲，混蛋是一种合理的方法，但将其应用于痉挛性个体有时会产生与直觉相反的结果，并且不会揭示整个工作空间中的运动障碍。为了更普遍地量化运动中的自发加速瞬变（SAT），设计了一种伪小波变换，该迭代迭代将角度轨迹与一系列直线近似值进行比较。累积线性拟合误差以屈曲角度表示，得出整个运动的SAT图。为了将SAT映射图与传统的平滑度度量进行比较，从中提取了两个标量指数：残余偏移偏差（RED），代表Deltatheta上的积分以及峰误差与平均误差之比（PEME）。 15名受试者（包括5名患有慢性中风的受试者）在其整个运动范围Deltatheta中以舒适的步伐进行了屈肘，其手臂支撑在横向平面上。地图显示，中风受试者的协调性明显低于对照组，通过RED分别测量：8.0 +/- 2.9 x 10（-3）与3.1 +/- 0.8 x 10（-3）和PEME：6.6 +/- 0.9 12.1 +/- 1.9，均P ＜0.001。可比较的抽动指标（包括综合平均抽动）在P <0.05的水平上未报告明显的性能缺陷。所有受试者的地图指标均独立于平均速度（与theta的相关性：rho0.31），但是中风受试者基于抽搐的指标与速度rho = 0.85呈虚假协变，这可能与平均逮捕期比率明显较高有关在卒中患者中（0.26 +/- 0.19对0.09 +/- 0.08，P <0.001）。我们得出的结论是，SAT映射可以在各种熟练水平上提供有关区域运动障碍的可靠信息。

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