Development of a Novel Intervention Guided by Neuromuscular Control Principles for Upper Extremity Neurorehabilitation after Stroke
Stroke survivors often face upper extremity motor impairments that include abnormal intermuscular coordination, which negatively affects individualized joint control. This lack of individualized coordination is one of the fundamental motor control problems that explain voluntary movement impairment post-stroke. In recent years, the concept of muscle synergy, here defined as a consistent ratio of co-activation of muscle across multiple muscles required to perform a motor task, has been effectively applied to characterize intermuscular coordination in neurologically intact individuals and stroke survivors. However, it is still largely unexplored if muscle synergy characteristics can be targeted and improved to enhance stroke-induced intermuscular coordination. Thus, developing non-invasive neurorehabilitation strategies to improve altered muscle synergy holds promise for advancing rehabilitative therapies. This dissertation mainly covers two upper extremity studies: 1) the generalizability of neuromuscular coordination strategies following stroke and its implication for neurorehabilitation, and 2) the development of an isometric muscle-synergy guided intervention to improve intermuscular coordination after stroke through human-machine interaction. The first study compared the neuromuscular control strategies underlying static and dynamic tasks. This study showed evidence of shared muscle synergy patterns after stroke and found that abnormalities in the activation profile vary across biomechanical conditions. For the second study, a novel isometric neuromuscular-guided intervention to improve neuromuscular coordination was designed and tested. The results showed the feasibility of modulating and improving stroke-induced intermuscular coordination to reduce motor impairment after stroke.
Portilla-Jiménez, Manuel Alejandro 1988-
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