In-Depth Analysis of Functional Corticomuscular Coupling after Stroke Using UEFD-PTE

Motor dysfunction is a prominent symptom following stroke, primarily attributed to neural network damage that disrupts motor control. However, the precise mechanism underlying motor control between the cerebral cortex and the muscle system after stroke remains unclear. Elucidating this complex mechanism can provide some scientific basis for rehabilitation treatment after stroke. The aim of this study was to investigate the complex multiband functional coupling between the cerebral cortex and the muscular system based on a novel functional cortical muscle coupling analysis method to shed light on the mechanism of multiband neuromuscular control after stroke. In this study, 64-channel of electroencephalogram (EEG) signals and electromyogram (EMG) signals encompassing pectoralis major, upper trapezius, anterior deltoids, middle deltoids, posterior deltoids, biceps, and triceps muscles were collected from 13 stroke patients and 13 healthy controls during the forward extension movement. Brain source localization and clustering methods were employed to identify active cortical regions associated with the movement, then a uniform empirical Fourier decomposition of EEG and EMG signals was performed, followed by the assessment of functional connectivity between active cortical regions and each muscle by calculating the partial transfer entropy. The results revealed significant differences in functional connectivity between stroke patients and healthy controls across different frequency bands, with the most pronounced coupling strength observed in the β band. The proposed coupling analysis method ensured the decomposition of EEG and EMG signals into the same frequency band, mitigating the problem of modal confounding and endpoint effects associated with signal decomposition. Furthermore, it effectively eliminated the adverse effects of indirect coupling on multichannel coupling analysis. Overall, this study’s coupling analysis provides valuable insights into the complex corticomuscular coupling after stroke, facilitating a comprehensive understanding of post-stroke neuromuscular dynamics by unraveling the intricate relationship between brain and muscle.