Computational Modeling of the Pendulum Test to Simulate Spasticity in the Elbow Joint

Computational models have been developed to help understand phenomena such as spasticity. In this study, we aim to develop a computational model using the Matlab-OpenSim interface to simulate the passive pendulum test in the elbow joint and evaluate whether the input of a neural excitation pattern with spasticity in the model would be sufficient to reproduce an altered kinematic pattern during an elbow pendulum test. We built a model with two segments that represent the humerus and radius bones, added two actuators to represent the biceps and triceps muscles, and the excitation values were obtained from the electromyography signal available in the literature. For the first simulation we used the electromyography (EMG) signal from a non-spastic person and for the last simulation was used the excitation values from a person with mild spasticity. Our results showed that it is possible to reproduce the pendulum test at the elbow joint, but modifications in the model are necessary to better reproduce the movement.