A comparison of the assessment of spasticity by the Wartenberg pendulum test and the Ashworth grading scale in patients with multiple sclerosis

Abstract

The Wartenberg pendulum test is an objective quantitative method for the assessment of muscle tone. We have compared the results of measurements of muscle tone using this method with traditional clinical assessments graded on the Ashworth scale. Two indices ( R₁ and R₂) were measured from the Wartenberg test. Both were related to readings from the Ashworth scale. The ratio R₂ (the ratio of the amplitude of the first swing to the difference in angle between the start and finish positions), however, showed a linear relationship throughout the range of spasticity tested in contrast to the curvilinear relationship shown by R₁ (the ratio of the amplitude of the first swing to the difference between the rebound angle and the start angle). Significant changes in the ratio R₂ without any corresponding change in the Ashworth grading were observed. It is concluded that the Wartenberg ratio R₂ and the Ashworth scale assess similar features of the muscle and/or its motor control, but that the pendulum test provides a more finely graded observer- independent measurement.