By Topic

A quantitative analysis of pendular motion of the lower leg in spastic human subjects

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Lin, D.C. ; Dept. of Biomed. Eng., Northwestern Univ., Chicago,, IL, USA ; Rymer, W.Z.

Gravity-induced oscillations of the lower leg in normal and spastic subjects were examined with a view towards evaluating a clinical test of spasticity called the pendulum test. For passive limb motion (in which no reflex excitation occurred), a second-order linear model did not provide an adequate description of the motion for either spastic or normal legs. System equations including nonlinear mechanical properties simulating asymmetries in the swing and amplitude dependent variations in stiffness and damping provided a more accurate description. For spastic limb motion (in which reflex excitation did occur) accurate simulation required components accounting for abnormal reflex activation, coinciding with the time course of EMG activation. These included increased stiffness and damping with their gains related to reflex EMG magnitude, and changes in the rest length of the stiffness. Comparison of numerical with experimental data showed that the nonlinear model simulated the motion accurately, with the variance accounted for usually exceeding 90%.

Published in:

Biomedical Engineering, IEEE Transactions on  (Volume:38 ,  Issue: 9 )