Effects of force and joint angle on fractal parameters of the myoelectric signal

In this paper we investigate the effect of force and joint angle on myoelectric signal parameters. In recent years, methods that have been previously used to analyze nonlinear chaotic dynamical systems have been applied to myoelectric signals. Nonlinear myoelectric signal parameters that have been used include the fractal dimension, estimated using the Katz method and Box-Counting methods, and the spectral slopes. Previous research has only examined effects of contractile force, whereas this research also includes joint angle effects. Results of this research suggest that the Katz and Box-Counting approaches used to estimate fractal dimension are not well suited for time functions, such as myoelectric signals. Results from the spectral slope parameters suggest that these parameters can track joint angle effects. A generalized model approach building upon the spectral slope method is proposed for future work.