Increased joint resistance is an important phenomenon in patients with cerebral palsy (CP), and is caused by a combination of neural and non-neural components. Spasticity is part of the neural component and is typically defined as velocity-dependent hyperactivity to passive stretch. Contracture can be defined as the non-neural component of hyper-resistance, and is due to increased passive tissue stiffness.
To what extent can we explain contracture by altered passive muscle properties?
To what extent can we explain spasticity by a (purely) velocity-dependent hyper-activity of the stretch reflex?
The velocity-dependent spasticity model has been implemented as a plug-in in OpenSim (https://simtk.org/home/spasticitymodel). We will show how this spasticity model can be applied, and how the model parameters as well as the passive muscle properties can be tuned based on slow and fast passive muscle stretches during instrumented spasticity assessment.