Objective

Although gait analysis has been widely adopted to describe Parkinson's disease (PD) dysfunctions during walking, few efforts have been made to understand muscle activity role. The current study aims to characterize lower-limb-muscle recruitment during walking in time-frequency domain, based on Continuous Wavelet Transform (CWT) analysis of surface-electromyography (sEMG) signal from lower-limb muscles.

Materials and methods

sEMG signals from Tibialis Anterior (TA), Gastrocnemius Lateralis (GL), Rectus Femoris (RF), and Biceps Femoris (BF) of 20 people with PD and 10 age-matched healthy controls (HC) were acquired during gait. sEMG signals were processed applying a CWT-based approach to assess the occurrence frequency (OF, i.e., the percentage of strides of each muscle activation occurrence) and the frequency content of each muscle activation (in Hz). These parameters are rarely quantified in PD.

Results

Compared to HC, people with PD displayed a significant decrease (p<0.05) in median OF on RF, BF, and TA, indicating a tendency to reduce the global involvement of lower-limb muscles. No significant differences (p>0.05) in OF were detected among muscle within the same population. No significant changes (p>0.05) in frequency content were revealed in PD.

Conclusion

This analysis suggests that people with PD are characterized by a reduced recruitment of those muscles typically adopted to finely control body-segment motion and a concomitant increased recruitment of those muscles mainly involved in locomotion. No substantial alteration in recruiting muscle fibers is associated with PD. These findings suggest that people with PD are inclined to adopt simpler muscular-recruitment strategies during walking, compared to HC.

中文翻译：

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帕金森病患者行走时简化的肌肉募集策略：肌电图信号的时频分析

客观的

尽管步态分析已被广泛用于描述步行过程中的帕金森病 (PD) 功能障碍，但很少有人努力了解肌肉活动的作用。目前的研究旨在基于下肢肌肉表面肌电图 (sEMG) 信号的连续小波变换 (CWT) 分析，在时频域中表征步行过程中下肢肌肉的募集。

材料和方法

在步态过程中获取 20 名 PD 患者和 10 名年龄匹配的健康对照 (HC) 的胫骨前肌 (TA)、腓肠肌外侧肌 (GL)、股直肌 (RF) 和股二头肌 (BF) 的 sEMG 信号。应用基于 CWT 的方法处理 sEMG 信号，以评估发生频率（OF，即每次肌肉激活发生的步幅百分比）和每次肌肉激活的频率内容（以 Hz 为单位）。这些参数在 PD 中很少被量化。

结果

与 HC 相比，PD 患者的 RF、BF 和 TA 的中位 OF 显着降低（p<0.05），表明下肢肌肉整体受累有减少的趋势。同一群体内的肌肉之间未检测到 OF 存在显着差异 (p>0.05)。PD 中频率内容没有显着变化 (p>0.05)。

结论

该分析表明，帕金森病患者的特点是，通常用于精细控制身体节段运动的肌肉募集减少，而主要参与运动的肌肉募集随之增加。募集肌纤维的显着改变与 PD 无关。这些发现表明，与正常人相比，帕金森病患者在步行时倾向于采用更简单的肌肉募集策略。