Ao Di, Sun Rui, Tong Kai-Yu, Song Rong
School of Engineering, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China.
Ann Biomed Eng. 2015 Apr;43(4):990-1002. doi: 10.1007/s10439-014-1150-1. Epub 2014 Oct 15.
To explore the stroke- and aging-induced neurological changes in paretic muscles from an entropy point of view, fuzzy approximate entropy (fApEn) was utilized to represent the complexity of EMG signals in elbow-tracking tasks. In the experiment, 11 patients after stroke and 20 healthy control subjects (10 young and 10 age-matched adults) were recruited and asked to perform elbow sinusoidal trajectory tracking tasks. During the tests, the elbow angle and electromyographic (EMG) signals of the biceps brachii and triceps brachii were recorded simultaneously. The results showed significant differences in fApEn values of both biceps and triceps EMG among four groups at six velocities (p < 0.01), with fApEn values in the following order: affected sides of stroke patients < unaffected sides of stroke patients < age-matched controls < young controls. A possible mechanism underlying the smaller fApEn values in the affected sides in comparison with aged-matched controls and in the aged individuals in comparison with young controls might be the reduction in the number and firing rate of active motor units. This method and index provide evidence of neurological changes after stroke and aging by complexity analysis of the surface EMG signals. Further studies are needed to validate and facilitate the application in clinic.
为了从熵的角度探讨中风和衰老引起的患侧肌肉神经学变化，采用模糊近似熵（fApEn）来表征肘部跟踪任务中肌电信号的复杂性。实验招募了11名中风后患者和20名健康对照者（10名年轻人和10名年龄匹配的成年人），并要求他们执行肘部正弦轨迹跟踪任务。测试过程中，同时记录肱二头肌和肱三头肌的肘部角度和肌电图（EMG）信号。结果显示，在六个速度下，四组肱二头肌和肱三头肌EMG的fApEn值存在显著差异（p < 0.01），fApEn值顺序如下：中风患者患侧 < 中风患者健侧 < 年龄匹配对照组 < 年轻对照组。与年龄匹配对照组相比，患侧fApEn值较小；与年轻对照组相比，老年人fApEn值较小，其潜在机制可能是活跃运动单位数量和放电频率的降低。该方法和指标通过对表面肌电信号进行复杂性分析，为中风和衰老后的神经学变化提供了证据。需要进一步研究以验证并促进其在临床中的应用。
