Rowley Molly, Warner Jayme, Harper Sara A, Beethe Anne Z, Whelan Robert, Ruddy Kathy L, Bolton David A E
Department of Kinesiology and Health Science, Utah State University, Logan, UT, USA.
Department of Kinesiology and Health Science, Utah State University, Logan, UT, USA; Sorenson Center for Clinical Excellence, Utah State University, Logan, UT, USA.
Gait Posture. 2022 Jun;95:56-62. doi: 10.1016/j.gaitpost.2022.04.009. Epub 2022 Apr 13.
Correlations between falls and individual differences in inhibitory control, suggest the ability to suppress automatic, but unwanted, action is important in fall prevention. Response inhibition has been a topic of considerable interest in the cognitive neuroscience community for many decades, bringing a wealth of techniques that could potentially inform assessment of reactive balance. For example, the stop signal task is a popular method to quantify inhibitory control ability.
Can we apply the stop signal task to measure response inhibition in a balance recovery task?
Twenty healthy, young adults completed a novel reactive balance test that required occasional suppression of a balance recovery step. Participants were released from a supported lean ('Go' cue) requiring them to quickly step forward to regain balance. On some trials, a tone ('Stop' cue) instructed participants to suppress a step and relax into a harness. Step trials were more frequent (80%) than stop trials (20%) to bias a rapid stepping response. The stop tone was presented at various delays following cable release, to manipulate task difficulty (i.e., longer delays make step suppression difficult). Individual differences in inhibitory control were determined using lift off times from force plates, and by contrasting muscle activation in failed compared to successful stop trials.
Most participants were able to successfully suppress a balance recovery step on occasion, allowing for accurate estimation of individual differences in inhibitory control. The successful suppression of a balance recovery step was more likely in the group (n = 10) where shorter stop signal delays were used (i.e., the task was easier).
While balance assessments often stress reflexive action, there is a need for methods that evaluate response inhibition. The present study leveraged a well-established cognitive test of inhibitory control to develop a method to quantify stopping ability in a reactive balance context.
跌倒与抑制控制方面的个体差异之间的相关性表明，抑制自动但不必要动作的能力在预防跌倒中很重要。几十年来，反应抑制一直是认知神经科学界相当感兴趣的话题，带来了大量可能有助于评估反应性平衡的技术。例如，停止信号任务是一种量化抑制控制能力的常用方法。
我们能否应用停止信号任务来测量平衡恢复任务中的反应抑制？
20名健康的年轻成年人完成了一项新颖的反应性平衡测试，该测试偶尔需要抑制平衡恢复步骤。参与者从支撑倾斜状态下被放开（“开始”信号），要求他们迅速向前迈步以重新获得平衡。在一些试验中，一个音调（“停止”信号）指示参与者抑制迈步并放松进入安全带。迈步试验比停止试验更频繁（80%），以偏向快速迈步反应。停止音调在电缆放开后的不同延迟时间出现，以操纵任务难度（即，延迟时间越长，抑制迈步越困难）。使用力板的离地时间，并通过对比失败的停止试验与成功的停止试验中的肌肉激活情况，来确定抑制控制方面的个体差异。
大多数参与者有时能够成功抑制平衡恢复步骤，从而能够准确估计抑制控制方面的个体差异。在使用较短停止信号延迟的组（n = 10）中，成功抑制平衡恢复步骤的可能性更大（即任务更容易）。
虽然平衡评估通常强调反射性动作，但需要评估反应抑制的方法。本研究利用一种成熟的抑制控制认知测试，开发了一种在反应性平衡情境中量化停止能力的方法。
