Background

Patients with Down Syndrome (DS) exhibit less efficient and unstable standing postural control. The specificities of somatosensorial deficits might result in a different utilization of resources and in distinct whole-body kinematic patterns, to date still unexplored. In this paper we aim at addressing multi-segmental coordination patterns in people with DS while maintaining standing balance under different visual conditions (open and closed eyes).

Methods

This cross-sectional observational cohort study involved two groups of 23 patients with DS and 12 healthy controls. A 30-s standing balance test allowed to extract (i) the length of the trajectory of the center-of-pressure sway and 95% confidence ellipse area from Ground Reaction forces, and (ii) Principal Movement (PM) components from full-body motion kinematics; the latter were obtained exploiting a Principal Component Analysis-based approach, also embracing a motor-control perspective through the evaluation of the number of modifications applied by the neuromuscular controller on segments' acceleration.

Findings

Trajectory length was significantly higher in patients; 95% ellipse confidence area did not differ between groups/condition. Postural movement components differed in people with DS from healthy controls not only in the “observable”, behavioural phenotype (PM3 and PM8), but also in the amount of activation of the associated control (PM1 to PM8, over-activated in DS) in all spatial directions.

Interpretation

Results reinforced the prevalence of a medio-lateral hip strategy (instead of an ankle strategy) in maintaining postural stability. Most important, they revealed a less frequent activation of postural patterns in all spatial directions.

中文翻译：

---

唐氏综合症的多节段姿势控制模式

背景

唐氏综合症（DS）患者表现出较低的效率和不稳定的站立姿势控制。体感缺陷的特殊性可能导致对资源的不同利用和不同的全身运动学模式，迄今为止尚未探索。在本文中，我们旨在解决DS患者的多段协调模式，同时在不同的视觉条件下（睁眼和闭眼）保持站立平衡。

方法

这项横断面观察性队列研究涉及两组，分别为23名DS患者和12名健康对照者。进行30秒钟的静置平衡测试，可以从地面反作用力中提取（i）压力中心摇摆轨迹的长度和95％置信椭圆面积，以及（ii）从全反作用力中提取主运动（PM）分量身体运动学；后者是通过基于主成分分析的方法获得的，并且还通过评估神经肌肉控制器对节段加速度施加的修改次数来包含运动控制的观点。

发现

患者的弹道长度明显更长；组/条件之间的95％椭圆置信度区域没有差异。DS患者的姿势运动成分与健康对照者不同，不仅在“可观察到的”，行为表型（PM3和PM8）方面，而且在与之相关的控件（PM1至PM8，在DS中过度激活）的激活量方面也不同。所有空间方向。

解释

结果增强了维持姿势稳定性的中外侧髋关节策略（而不是踝关节策略）的患病率。最重要的是，他们发现在所有空间方向上姿势模式的激活频率都较低。