Delcamp Célia, Chalard Alexandre, Srinivasan Ramesh, Cramer Steven C
Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States.
California Rehabilitation Institute, Los Angeles, CA, United States.
Front Neurosci. 2024 Aug 12;18:1415134. doi: 10.3389/fnins.2024.1415134. eCollection 2024.
Stroke leads to motor deficits, requiring rehabilitation therapy that targets mechanisms underlying movement generation. Cortical activity during the planning and execution of motor tasks can be studied using EEG, particularly via the Event Related Desynchronization (ERD). ERD is altered by stroke in a manner that varies with extent of motor deficits. Despite this consensus in the literature, defining precisely the temporality of these alterations during movement preparation and performance may be helpful to better understand motor system pathophysiology and might also inform development of novel therapies that benefit from temporal resolution.
Patients with chronic hemiparetic post-stroke ( = 27; age 59 ± 14 years) and age-matched healthy right-handed control subjects ( = 23; 59 ± 12 years) were included. They performed a shoulder rotation task following the onset of a stimulus. Cortical activity was recorded using a 256-electrode EEG cap. ERD was calculated in the beta frequency band (15-30 Hz) in ipsilesional sensorimotor cortex, contralateral to movement. The ERD was compared over time between stroke and control subjects using permutation tests. The correlation between upper extremity motor deficits (assessed by the Fugl-Meyer scale) and ERD over time was studied in stroke patients using Spearman and permutation tests.
Patients with stroke showed on average less beta ERD amplitude than control subjects in the time window of -350 to 50 ms relative to movement onset ((46) = 2.8, = 0.007, Cohen's d = 0.31, 95% CI [0.22: 1.40]). Beta-ERD values correlated negatively with the Fugl-Meyer score during the time window -200 to 400 ms relative to movement onset (Spearman's = -0.54, = 0.003, 95% CI [-0.77 to -0.18]).
Our results provide new insights into the precise temporal changes of ERD after hemiparetic stroke and the associations they have with motor deficits. After stroke, the average amplitude of cortical activity is reduced as compared to age-matched controls, and the extent of this decrease is correlated with the severity of motor deficits; both were true during motor programming and during motor performance. Understanding how stroke affects the temporal dynamics of cortical preparation and execution of movement paves the way for more precise restorative therapies. Studying the temporal dynamics of the EEG also strengthens the promising interest of ERD as a biomarker of post-stroke motor function.
中风会导致运动功能障碍，需要针对运动产生机制的康复治疗。运动任务规划和执行过程中的皮层活动可以通过脑电图（EEG）进行研究，特别是通过事件相关去同步化（ERD）。中风会改变ERD，其改变方式因运动功能障碍程度而异。尽管文献中有此共识，但精确确定这些改变在运动准备和执行过程中的时间性，可能有助于更好地理解运动系统病理生理学，也可能为受益于时间分辨率的新型疗法的开发提供信息。
纳入慢性中风后偏瘫患者（n = 27；年龄59±14岁）和年龄匹配的健康右利手对照受试者（n = 23；59±12岁）。他们在刺激开始后执行肩部旋转任务。使用256电极EEG帽记录皮层活动。在与运动对侧的患侧感觉运动皮层的β频段（15 - 30Hz）计算ERD。使用置换检验比较中风患者和对照受试者随时间的ERD。使用Spearman检验和置换检验研究中风患者上肢运动功能障碍（通过Fugl - Meyer量表评估）与随时间的ERD之间的相关性。
相对于运动开始，在 - 350至50ms的时间窗口内，中风患者的β ERD平均幅度低于对照受试者（t(46) = 2.8，p = 0.007，Cohen's d = 0.31，95% CI [0.22: 1.40]）。相对于运动开始，在 - 200至400ms的时间窗口内，β - ERD值与Fugl - Meyer评分呈负相关（Spearman's ρ = - 0.54，p = 0.003，95% CI [- 0.77至 - 0.18]）。
我们的结果为偏瘫性中风后ERD的精确时间变化及其与运动功能障碍的关联提供了新见解。中风后，与年龄匹配的对照相比，皮层活动的平均幅度降低，且这种降低程度与运动功能障碍的严重程度相关；在运动编程和运动执行过程中均如此。了解中风如何影响皮层运动准备和执行的时间动态，为更精确的恢复性治疗铺平了道路。研究EEG的时间动态也增强了ERD作为中风后运动功能生物标志物的潜在价值。
