Functional Muscle Network in Post-stroke Patients during Quiet Standing

The overall muscle activation of post-stroke patients during standing has not been well understood. Functional muscle network provides a tool to quantify the functional synchronization across a large number of muscles. In order to investigating the functional muscle network of stroke survivors during quiet standing, we recruited 8 post-stroke hemiplegic patients and required them to stand still for 30 s with eyes open and closed. Surface electromyography signals were recorded from 16 muscles in abdomen, buttocks and lower limbs. The functional muscle networks of paretic side and healthy side were built by multiplex recurrence network approach. The topological characteristics of functional muscle network was quantified by parameters of multiplex network and weighted network. The results showed that the dynamical similarities of muscles on paretic side were reduced, and the dynamical connections of muscles on paretic side were weakened. Without visual feedback, the muscles activated in a more similar mode. The stroke led to lower synchronization of the muscle activation, and decreased efficiency of information transmission between muscles. When subjects stood with eyes closed, the muscles activated in a more deterministic pattern. The research opens new horizons to detect the overall muscle activation when stroke patients stand quietly, and can provide a theoretical basis for understanding the motor dysfunction caused by stroke.