Difference in bilateral lower limb muscle synergy mode for gait in patients after unilateral anterior cruciate ligament reconstruction / 中国康复理论与实践

ObjectiveTo investigate the difference in bilateral lower limb muscle synergy mode during gait in patients after unilateral anterior cruciate ligament reconstruction. MethodsElectromyography from bilateral lower limb muscles during gait were collected from twelve male and eight female patients after unilateral anterior cruciate ligament reconstruction in Affiliated Hospital of Wuhan Sports University, from April to June, 2023. The data were analyzed using non-negative matrix decomposition algorithm to extract the number of muscle synergies in the affected and unaffected legs, the time to peak activation of muscle synergies and the relative weights of the muscles. ResultsSix types of muscle synergy were identified in the unaffected leg of males during gait, while five types were identified in the affected leg, lacking synergy 2 that mainly from the tibialis anterior muscle. Six types of muscle synergy were identified in both legs in females during gait. There was no significant difference in the time to peak activation of muscle synergies between both legs in males (P > 0.05). However, the time to peak activation of muscle synergies increased in females in the affected leg for synergy 3 and synergy 5 (P < 0.05). The relative weight of the rectus femoris was lower in synergy 1 in the affected leg in males (P < 0.05). For female, the relative weight of the vastus lateralis was higher and the relative weight of the biceps femoris was lower in synergy 2 in the affected leg in females (P < 0.05); while the relative weight of the rectus femoris was lower in synergy 3 (P < 0.05), and the relative weight of the biceps femoris was lower in synergy 6 (P < 0.05). ConclusionMales would freeze the muscle synergy dominating ankle dorsiflexion in affected leg to enhance ankle stability, and reduce the relative weight of rectus femoris during the loading response phase to weaken the knee landing cushioning. However, females would delay the activation of synergies dominating in loading response phase and the mid-stance phase, enhance the relative weight of vastus lateralis during the loading response phase, and reduce the relative weights of rectus femoris in the loading response phase and the relative weight of biceps femoris in the mid-stance phase, to limit knee flexion.

Multi-modal synergistic quantitative analysis and rehabilitation assessment of lower limbs for exoskeleton / 生物医学工程学杂志

In response to the problem that the traditional lower limb rehabilitation scale assessment method is time-consuming and difficult to use in exoskeleton rehabilitation training, this paper proposes a quantitative assessment method for lower limb walking ability based on lower limb exoskeleton robot training with multimodal synergistic information fusion. The method significantly improves the efficiency and reliability of the rehabilitation assessment process by introducing quantitative synergistic indicators fusing electrophysiological and kinematic level information. First, electromyographic and kinematic data of the lower extremity were collected from subjects trained to walk wearing an exoskeleton. Then, based on muscle synergy theory, a synergistic quantification algorithm was used to construct synergistic index features of electromyography and kinematics. Finally, the electrophysiological and kinematic level information was fused to build a modal feature fusion model and output the lower limb motor function score. The experimental results showed that the correlation coefficients of the constructed synergistic features of electromyography and kinematics with the clinical scale were 0.799 and 0.825, respectively. The results of the fused synergistic features in the K-nearest neighbor (KNN) model yielded higher correlation coefficients ( r = 0.921, P < 0.01). This method can modify the rehabilitation training mode of the exoskeleton robot according to the assessment results, which provides a basis for the synchronized assessment-training mode of "human in the loop" and provides a potential method for remote rehabilitation training and assessment of the lower extremity.

Analysis of muscle synergy and muscle functional network at different walking speeds based on surface electromyographic signal / 生物医学工程学杂志

An in-depth understanding of the mechanism of lower extremity muscle coordination during walking is the key to improving the efficacy of gait rehabilitation in patients with neuromuscular dysfunction. This paper investigates the effect of changes in walking speed on lower extremity muscle synergy patterns and muscle functional networks. Eight healthy subjects were recruited to perform walking tasks on a treadmill at three different speeds, and the surface electromyographic signals (sEMG) of eight muscles of the right lower limb were collected synchronously. The non-negative matrix factorization (NNMF) method was used to extract muscle synergy patterns, the mutual information (MI) method was used to construct the alpha frequency band (8-13 Hz), beta frequency band (14-30 Hz) and gamma frequency band (31-60 Hz) muscle functional network, and complex network analysis methods were introduced to quantify the differences between different networks. Muscle synergy analysis extracted 5 muscle synergy patterns, and changes in walking speed did not change the number of muscle synergy, but resulted in changes in muscle weights. Muscle network analysis found that at the same speed, high-frequency bands have lower global efficiency and clustering coefficients. As walking speed increased, the strength of connections between local muscles also increased. The results show that there are different muscle synergy patterns and muscle function networks in different walking speeds. This study provides a new perspective for exploring the mechanism of muscle coordination at different walking speeds, and is expected to provide theoretical support for the evaluation of gait function in patients with neuromuscular dysfunction.

Advance of Muscle Synergy Theory in Rehabilitation Assessment for Children with Cerebral Palsy (review) / 中国康复理论与实践

The muscle synergy theory starts from the motor control model, focuses on the neural control function. This paper introduced the theory of muscle synergy, the relationship between muscle synergy and conditions of cerebral palsy patients, and its application in cerebral palsy assessment and rehabilitation. More researches are needed to explore on the details of neuromuscular pattern.