Nonlinear characteristics and functional analysis of masseter electromyography

Abstract

The C-C method was adopted to analyze the nonlinear characteristics of masseter electromyography (EMG) signals and the chaotic degree by the largest Lyapunov exponent (LLE) of different genders and sides. First, the embedding dimension and the delay time were obtained through this method, then the phase space was reconstructed to resume the chaotic attractor and determine the LLE. The result shows that the trajectory of attractor is denser than Chen’s attractor, and the LLE is positive, which means that not only the signal has the character of chaos, but also the chaotic degree of masseter EMG is relatively high. According to the value of the LLE, the chaotic degree of men’s masseter EMG is higher than that of women’s; when the dentition is normal, the chaotic degree of two sides is almost the same. Then, a conclusion can be deduced that if the LLE of both sides are in great difference, the unilateral mastication is likely to exist, which means that the nonlinear characteristics of masseter EMG can be applied to predict the unilateral mastication.

Keywords

nonlinear characteristic / masseter electromyograph / C-C Method / phase space reconstruction / attractor / Lyapunov exponent

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