Quantitative clinical measure of spasticity in children with cerebral palsy.

Abstract

This investigation developed an objective measure to quantify the degree of spasticity. Specifications included a single variable that integrated key elements characterizing spasticity: velocity, range of motion, and resistance to passive motion. A dynamometer at a children's hospital quantified the passive resistance of the hamstrings to knee extension for a range of motion at 4 different speeds for the prospective descriptive investigation. A convenience sample of six children with able bodies and 17 children with spastic diplegic cerebral palsy volunteered. DATA PROCESSING: Torque-angle data were processed to calculate the work done by the machine on the children for each speed and then determine the slope of the work-velocity curves. This slope was considered to be the measure of spasticity and it was hypothesized that children with cerebral palsy would have a greater slope than children with able bodies. An independent test determined whether a significant difference existed between groups (p < .05). Torque-angle data for children with able bodies indicated little change in passive resistance as a function of speed. Similar data for children with cerebral palsy indicated larger resistive torques with increasing speed. Slope from the work-velocity data was close to zero for children with able bodies [.003 J/(degrees/sec)], while the corresponding slope for children with cerebral palsy was approximately 10 times greater [.031 J/(degrees/sec)] and significantly different (p < .05). The slope of the work-velocity data integrates three major components characterizing spasticity, it is a single number that can easily be evaluated and interpreted in a clinical setting, and it utilizes a machine that is available at many centers.