The application of air bag technology: An objective clinical measure of involuntary muscle spasm

Objectives: To develop a technique which could objectively monitor and quan tify spasms in spinal cord injured persons. Methods: This technique used accelerometers to detect movements in the limb caused by spasms. Accelerometer signals from movements caused by spasms an d a variety of movements caused by other subject activities (movement in a wheelchair, transfers etc) were recorded and linear discriminant analysis w as used to distinguish between spasms and other activities. Individual spas ms were quantified by their duration, magnitude and energy and were recorde d over a 24-h period. Results: Limb movements caused by spasms were shown to be well correlated w ith the EMG activity of the muscles causing the movement. Movements caused by spasms and movements caused by other subject activities could be reliabl y distinguished. Subjects showed a characteristic spasm pattern and it was possible to quantify the severity of the spasms and to determine precisely when they occurred. Conclusion: This technique for monitoring and quantifying spasms has the po tential to be used as a clinical tool to aid in the evaluation and prescrip tion of treatment.