Department of Health Sciences and Technology, Institute of Human Movement Sciences and Sport, ETH Zurich, Zurich, Switzerland.
Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
Physiol Rep. 2020 Feb;8(4):e14378. doi: 10.14814/phy2.14378.
Corticomuscular (CMC) and intramuscular (intraMC) coherence represent measures of corticospinal interaction. Both CMC and intraMC can be assessed during human locomotion tasks, for example, while walking. Corticospinal control of gait can deteriorate during the aging process and CMC and intraMC may represent an important monitoring means. However, it is unclear whether such assessments represent a reliable tool when performed during walking in an ecologically valid scenario and whether age-related differences may occur. Wireless surface electroencephalography and electromyography were employed in a pilot study with young and old adults during overground walking in two separate sessions. CMC and intraMC analyses were performed in the gathered beta and lower gamma frequencies (i.e., 13-40 Hz). Significant log-transformed coherence area was tested for intersessions test-retest reliability by determining intraclass correlation coefficient (ICC), yielding to low reliability in CMC in both younger and older adults. intraMC exclusively showed low reliability in the older adults, whereas intraMC in the younger adults revealed similar values as previously reported: test-retest reliability [ICC (95% CI): 0.44 (-0.23, 0.87); SEM: 0.46; MDC: 1.28; MDC%: 103; Hedge's g (95% CI): 0.54 (-0.13, 1.57)]. Significant differences between the age groups were observed in intraMC by either comparing the two groups with the first test [Hedge's g (95% CI): 1.55 (0.85, 2.15); p-value: .006] or with the retest data [Hedge's g (95% CI): 2.24 (0.73, 3.70); p-value: .005]. Notwithstanding the small sample size investigated, intraMC seems a moderately reliable assessment in younger adults. The further development and use of this measure in practical settings to infer corticospinal interaction in human locomotion in clinical practice is warranted and should help to refine the analysis. This necessitates involving larger sample sizes as well as including a wider number of lower limb muscles. Moreover, further research seems warranted by the observed differences in modulation mechanisms of corticospinal control of gait as ascertained by intraMC between the age groups.
皮质肌（CMC）和肌内（intraMC）相干性代表皮质脊髓相互作用的测量。在人类运动任务期间，例如在行走期间，可以评估 CMC 和 intraMC。随着年龄的增长，步态的皮质脊髓控制可能会恶化，CMC 和 intraMC 可能代表重要的监测手段。然而，尚不清楚在生态上有效的情况下进行行走时，这些评估是否代表可靠的工具，以及是否会出现与年龄相关的差异。在两次单独的会议中，使用无线表面脑电图和肌电图对年轻和老年成年人进行了一项初步研究。在采集的β和较低的伽马频带（即 13-40 Hz）中进行了 CMC 和 intraMC 分析。通过确定组内相关系数（ICC），对跨会话测试-重测可靠性进行了对数变换相干面积的检验，结果显示年轻和老年成年人的 CMC 可靠性均较低。仅在老年人中 intraMC 显示出较低的可靠性，而年轻人的 intraMC 则显示出与先前报道相似的值：测试-重测可靠性[ICC（95%CI）：0.44（-0.23，0.87）; SEM：0.46; MDC：1.28; MDC%：103; Hedge's g（95%CI）：0.54（-0.13，1.57）]。通过比较两组与第一次测试[Hedge's g（95%CI）：1.55（0.85，2.15）; p 值：.006]或与重测数据[Hedge's g（95%CI）：2.24（0.73，3.70）; p 值：.005]，在 intraMC 中观察到年龄组之间存在显著差异。尽管研究的样本量较小，但 intraMC 在年轻人中似乎是一种中等可靠的评估。需要进一步开发和在实际环境中使用这种措施，以推断临床实践中人类运动的皮质脊髓相互作用，并应有助于完善分析。这需要涉及更大的样本量，并包括更多的下肢肌肉。此外，观察到年龄组之间步态皮质脊髓控制的调制机制存在差异，这表明需要进一步研究 intraMC。
