Muscle rigidity evaluation of the Parkinson's disease patients based on a mathematical model of muscle

Abstract

Neurologists evaluate the severity (5 states: 0~4) of the muscle rigidity by their perception of resistance to passive movement based on UPDRS part III. Endo developed the measurement system to evaluate muscle rigidity quantitatively based on the mathematical model explaining the resistance torque by the elastic component of the antagonistic muscle. The value of the elastic coefficient in the model was estimated that best fits the measured elbow joint angle data. In this study, we extend the model to take viscous and contraction components into accounts. We analyzed the data from 80 Parkinson's disease patients, and showed that AIC of the presented model was lower than the previous model in most cases. The elastic coefficients estimated using the presented model significantly increased as the severity increased. The discrimination ratio between severity 1 and 3 or more was 90% using logistic discrimination.