Research Article Parkinsonian Rigidity Depends on the Velocity of Passive Joint Movement

Copyright © 2015 Takuyuki Endo et al.This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. It has been long believed that Parkinsonian rigidity is not velocity-dependent based on the neurological examination. However, this has not been verified scientifically. Methods. The elbow joints of 20 Parkinson’s disease patients were passively flexed and extended, and two characteristic values, the elastic coefficient (elasticity) and the difference in bias (difference in torque measurements for extension and flexion), were identified from a plot of the angle and torque characteristics. Flexion and extension were done at two different velocities, 60∘/s and 120∘/s, and a statistical analysis was performed to determine whether the changes in these characteristic values were velocity-dependent. Results.The elastic coefficient was not velocity-dependent, but the difference in bias increased in a velocity-dependent manner