O'Reilly David, Delis Ioannis
School of Biomedical sciences, University of Leeds, Leeds, UK.
Exp Brain Res. 2024 Dec 23;243(1):31. doi: 10.1007/s00221-024-06973-x.
Current clinical assessment tools don't fully capture the genuine neural deficits experienced by chronic stroke survivors and, consequently, they don't fully explain motor function throughout everyday life. Towards addressing this problem, here we aimed to characterise post-stroke alterations in upper-limb control from a novel perspective to the muscle synergy by applying, for the first time, a computational approach that quantifies diverse types of functional muscle interactions (i.e. functionally-similar (redundant), -complementary (synergistic) and -independent (unique)). From single-trials of a simple forward pointing movement, we extracted networks of functionally diverse muscle interactions from chronic stroke survivors and unimpaired controls, identifying shared and group-specific modules across each interaction type (i.e. redundant, synergistic and unique). Reconciling previous studies, we found evidence for both the concurrent preservation of healthy functional modules post-stroke and muscle network structure alterations underpinned by systemic muscle interaction re-weighting and functional reorganisation across all interaction types. Cluster analysis of stroke survivors revealed two distinct patient subgroups from each interaction type that all distinguished less impaired individuals who were able to adopt novel motor patterns different to unimpaired controls from more severely impaired individuals who did not. Our work here provides a nuanced account of post-stroke functional impairment and, in doing so, paves new avenues towards progressing the clinical use case of muscle synergy analysis.
当前的临床评估工具无法完全捕捉慢性中风幸存者所经历的真正神经缺陷，因此，它们无法充分解释日常生活中的运动功能。为了解决这个问题，我们旨在从一个全新的角度，即肌肉协同作用，来描述中风后上肢控制的变化。我们首次应用了一种计算方法，该方法可以量化不同类型的功能性肌肉相互作用（即功能相似（冗余）、互补（协同）和独立（独特））。从简单向前指动作的单次试验中，我们从慢性中风幸存者和未受损对照组中提取了功能多样的肌肉相互作用网络，识别出每种相互作用类型（即冗余、协同和独特）中共享的和特定组别的模块。与之前的研究一致，我们发现了中风后健康功能模块同时保留的证据，以及所有相互作用类型中系统性肌肉相互作用重新加权和功能重组所支撑的肌肉网络结构改变。对中风幸存者的聚类分析显示，每种相互作用类型都有两个不同的患者亚组，所有亚组都区分出了受损较轻、能够采用与未受损对照组不同的新运动模式的个体，以及受损较重、无法采用新运动模式的个体。我们在此的工作对中风后的功能损害进行了细致入微的描述，从而为推进肌肉协同作用分析的临床应用案例开辟了新途径。
