Muscle synergies approach and perspective on application to robot-assisted rehabilitation

Muscle synergies have been described as a neural strategy to simplify the control of the redundant motor actuators leading human movement and have been used to investigate motor coordination in healthy subjects and patients with neurological disorders. Here, we recap the theoretical framework underlying the identification of muscle synergies. Then, we summarize how muscle synergies are modified by neuropathologies and their potential for neurorehabilitation. Finally, we report on how they can be used to both assess the effectiveness of robot-aided rehabilitation and design innovative control strategies. This chapter is expected to highlight novel perspectives for robot-aided rehabilitation based on the analysis of muscle synergies. It is suitable for readers new to the concept of muscle synergies willing to be introduced to this topic, or already familiar with the matter and interested in a deeper analysis of its implications in neurorehabilitation, or for roboticists looking for new strategies to improve robotic rehabilitation.