Department of Physical Therapy, Steinhardt School of Culture Education and Human Development, New York University, New York, New York, USA.
Department of Dance, Tisch School of the Arts, New York University, New York, New York, USA.
J Mot Behav. 2022;54(4):466-479. doi: 10.1080/00222895.2021.2013768. Epub 2021 Dec 13.
How postural responses change with sensory perturbations while also performing a cognitive task is still debatable. This study investigated this question via comprehensive assessment of postural sway, head kinematics and their coupling. Twenty-three healthy young adults stood in tandem with eyes open or wearing the HTC Vive Head-Mounted Display (HMD) with a static or dynamic (i.e., movement in the anterior-posterior direction at 5 mm or 32 mm at 0.2 Hz) 3-wall stars display. On half of the trials, participants performed a cognitive serial subtraction task. Medio-lateral center-of-pressure (COP) path significantly increased with the cognitive task, particularly with dynamic visuals whereas medio-lateral variance decreased with the cognitive task. Head path and velocity significantly increased with the cognitive task in both directions while variance decreased. Head-COP cross-correlations ranged between 0.78 and 0.66. These findings, accompanied by frequency analysis, suggest that postural control switched to primarily relying on somatosensory input under challenging cognitive load conditions. Several differences between head and COP suggest that head kinematics contribute an important additional facet of postural control and the relationship between head and COP may depend on task and stance position. The potential of HMDs for clinical assessments of balance needs to be further explored.
在执行认知任务的同时，姿势反应如何随着感觉扰动而变化仍存在争议。本研究通过对姿势摆动、头部运动及其耦合的综合评估来研究这个问题。23 名健康的年轻成年人睁开眼睛或戴着 HTC Vive 头戴式显示器（HMD），以静态或动态（即，以 0.2 Hz 的 5 毫米或 32 毫米的速度在前后方向移动）的 3 壁星显示站立。在一半的试验中，参与者执行认知串行减法任务。在认知任务中，尤其是在动态视觉刺激下，中-侧位压力中心（COP）轨迹显著增加，而中-侧方差减小。在两个方向上，头部轨迹和速度随着认知任务的进行显著增加，而方差减小。头-COP 互相关系数在 0.78 到 0.66 之间。这些发现，加上频率分析，表明在具有挑战性的认知负荷条件下，姿势控制切换为主要依赖于躯体感觉输入。头部和 COP 之间的几个差异表明，头部运动为姿势控制提供了一个重要的附加方面，并且头部和 COP 之间的关系可能取决于任务和站立位置。HMD 用于平衡临床评估的潜力需要进一步探索。
