England Derek, Ruddy Kathy L, Dakin Christopher J, Schwartz Sarah E, Butler Blake, Bolton David A E
Department of Kinesiology and Health Science, Utah State University, Logan, UT 84322, USA.
School of Psychology and Institute of Neuroscience, Trinity College Dublin, Dublin D02 PN40, Ireland.
Brain Sci. 2021 May 15;11(5):643. doi: 10.3390/brainsci11050643.
In young adults, performance on a test of response inhibition was recently found to be correlated with performance on a reactive balance test where automated stepping responses must occasionally be inhibited. The present study aimed to determine whether this relationship holds true in older adults, wherein response inhibition is typically deficient and the control of postural equilibrium presents a greater challenge. Ten participants (50+ years of age) completed a seated cognitive test (stop signal task) followed by a reactive balance test. Reactive balance was assessed using a modified lean-and-release system where participants were required to step to regain balance following perturbation, or suppress a step if an obstacle was present. The stop signal task is a standardized cognitive test that provides a measure of the speed of response inhibition called the Stop Signal Reaction Time (SSRT). Muscle responses in the legs were compared between conditions where a step was allowed or blocked to quantify response inhibition of the step. The SSRT was significantly related to leg muscle suppression during balance recovery in the stance leg. Thus, participants that were better at inhibiting their responses in the stop signal task were also better at inhibiting an unwanted leg response in favor of grasping a supportive handle. The relationship between a seated cognitive test using finger responses and leg muscle suppression when a step was blocked indicates a context-independent, generalized capacity for response inhibition. This suggests that a simple cognitive test such as the stop signal task could be used clinically to predict an individual's capacity for adapting balance reactions and fall risk. The present results provide support for future studies, with larger samples, to verify this relationship between stop signal reaction time and leg response during balance recovery.
最近发现，在年轻人中，反应抑制测试的表现与反应性平衡测试的表现相关，在反应性平衡测试中，必须偶尔抑制自动踏步反应。本研究旨在确定这种关系在老年人中是否成立，因为老年人的反应抑制通常不足，而且姿势平衡的控制面临更大挑战。10名参与者（年龄在50岁及以上）完成了一项坐姿认知测试（停止信号任务），随后进行了反应性平衡测试。使用改良的倾斜-释放系统评估反应性平衡，要求参与者在受到干扰后迈步恢复平衡，或者如果有障碍物则抑制迈步。停止信号任务是一项标准化的认知测试，提供了一种称为停止信号反应时间（SSRT）的反应抑制速度测量方法。比较了允许迈步或阻止迈步两种情况下腿部的肌肉反应，以量化对迈步的反应抑制。SSRT与单腿平衡恢复过程中的腿部肌肉抑制显著相关。因此，在停止信号任务中更善于抑制反应的参与者，在抑制不必要的腿部反应以抓住支撑手柄方面也表现得更好。使用手指反应的坐姿认知测试与迈步被阻止时腿部肌肉抑制之间的关系表明，存在一种与情境无关的、广义的反应抑制能力。这表明，像停止信号任务这样简单的认知测试可以在临床上用于预测个体适应平衡反应的能力和跌倒风险。目前的结果为未来更大样本量的研究提供了支持，以验证停止信号反应时间与平衡恢复过程中腿部反应之间的这种关系。
