Altered Muscle Networks in Post-Stroke Survivors
Functional interactions among muscles, indicated by muscle networks, reflect the effort of the central nervous system in reducing the redundancy of the musculoskeletal system in motor control. Efforts have been devoted to characterizing muscle network patterns in healthy subjects, however, alterations of muscle networks associated with stroke remain unexplored. Muscle networks were assessed for eight key upper extremity muscles in mild, moderate, and severe stroke survivors and compared to healthy controls to identify stroke linked alterations in the neural oscillatory drive to muscles. Intermuscular coherence was computed for all possible muscle connections and were further decomposed via non-negative matrix factorization (NNMF) to identify the common spectral patterns of coherence underlying the muscle networks. Results demonstrated that the number of identified muscle networks during force generation is reduced in stroke survivors compared to healthy controls, and the number decreases as the severity of stroke increases. Stroke patients also showed reduced coherence of higher frequencies, particularly in the in the alpha, beta, and gamma bands. The findings in this study could provide a new prospective for understanding the motor control recovery during post-stroke rehabilitation and inform future motor rehabilitation for post-stroke survivors.