Upper Limbs Muscle Co-contraction Changes Correlated With the Impairment of the Corticospinal Tract in Stroke Survivors: Preliminary Evidence From Electromyography and Motor-Evoked Potential

Abstract

ObjectiveIncreased muscle co-contraction of the agonist and antagonist muscles during voluntary movement is commonly observed in the upper limbs of stroke survivors. Much remain to be understood about the underlying mechanism. The aim of the study is to investigate the correlation between increased muscle co-contraction and the function of the corticospinal tract (CST).MethodsNine stroke survivors and nine age-matched healthy individuals were recruited. All the participants were instructed to perform isometric maximal voluntary contraction (MVC) and horizontal task which consist of sponge grasp, horizontal transportation, and sponge release. We recorded electromyography (EMG) activities from four muscle groups during the MVC test and horizontal task in the upper limbs of stroke survivors. The muscle groups consist of extensor digitorum (ED), flexor digitorum (FD), triceps brachii (TRI), and biceps brachii (BIC). The root mean square (RMS) of EMG was applied to assess the muscle activation during horizontal task. We adopted a co-contraction index (CI) to evaluate the degree of muscle co-contraction. CST function was evaluated by the motor-evoked potential (MEP) parameters, including resting motor threshold, amplitude, latency, and central motor conduction time. We employed correlation analysis to probe the association between CI and MEP parameters.ResultsThe RMS, CI, and MEP parameters on the affected side showed significant difference compared with the unaffected side of stroke survivors and the healthy group. The result of correlation analysis showed that CI was significantly correlated with MEP parameters in stroke survivors.ConclusionThere existed increased muscle co-contraction and impairment in CST functionality on the affected side of stroke survivors. The increased muscle co-contraction was correlated with the impairment of the CST. Intervention that could improve the excitability of the CST may contribute to the recovery of muscle discoordination in the upper limbs of stroke survivors.

Effects of EMG-based robot for upper extremity rehabilitation on post-stroke patients: a systematic review and meta-analysis

“…Following a stroke occurrence, the injured brain undergoes a reorganization process that involves recruiting pathways homologous to the damaged regions in function but distinct in anatomy, synaptogenesis, dendritic arborization, and reinforcing synaptic connections ( Rossini et al, 2003 ). Such adaptive brain changes seem to be closely related to rehabilitation and motor training, contributing to the improvement of functional outcomes ( Chen et al, 2018 ; Sampaio-Baptista et al, 2018 ; Sheng et al, 2022 ). High-intensity repetitive training is one of the principles of post-stroke rehabilitation ( Langhorne et al, 2011 ).…”

“…In addition, signals from EMG-based robot can reflect the voluntary movement intention of patients in real time ( Rong et al, 2015 ; Zhuang et al, 2021 ), which may increase active patient participation and promote interaction between humans and machines. Recording of muscle activity by EMG has proved to be helpful to explore the activity state of muscle tissue and the control mechanism of the nervous system under different task states after stroke ( Ma et al, 2017 ; Chen et al, 2018 ), and then be useful for evaluating central and peripheral determinants of motor dysfunction which facilitates the understanding of mechanism behind rehabilitation intervention ( Sheng et al, 2022 ; Li et al, 2023 ). Voluntary motor intention is crucial in the rehabilitation of motor function after stroke ( Yang et al, 2022 ).…”

The interaction between changes of muscle activation and cortical network dynamics during isometric elbow contraction: a sEMG and fNIRS study

“…The CCI can evaluate the degree of upper limb muscle activation and muscle coordination ( Sheng et al, 2022 ). As shown in Figure 7 , the results revealed that the CCI of EMG signals increased significantly in both dominant and non-dominant sides with higher MVC force.…”

Myogenic and cortical evoked potentials vary as a function of stimulus pulse geometry delivered in the subthalamic nucleus of Parkinson’s disease patients

“…The CPL− condition increased by 47% (95% CI 41-52) per mA. SB− increased by 46% (95% CI 41-52) per mA, while SB+ increased by similarly by 41% (95% CI [35][36][37][38][39][40][41][42][43][44][45][46]. The CPF+ increased by 33% (95% CI 27-39) per mA and CPL+ increased by 28% (95% CI 23-34) per mA.…”