Neuro-musculo-skeletal Model for Simulation of Spasticity

Abstract

The purposes of this study are to construct a neuro-musculo-skeletal model representing characteristics of spasticity and to clarify the biomechanical features of spasticity through the computational model. This study constructed two type models : a pendulum test model and a spastic gait model. The pendulum test model had one degree of freedom at the knee joint, and the spastic gait model had three-dimensional entire-body structure. Stretch reflex by the muscle spindle and elastic property of the muscle were mainly formulated in the neuronal model. Two types of spastic gait were investigated : muscle contracture and increasing of the stretch reflex. As the results, the pendulum movement well represented the features of spastic pendulum one, and the walking model synthesized walking motion with compensatory motion such as raise-up motion of pelvis, which is often observed in spastic gait. Virtual treatment such as selective dorsal rhizotomy was performed by changing transmissibility of the signal from the muscle spindle. The effects of several treatments for spasticity were also evaluated from variation of the gait pattern.