Abstract—An electrogastrogram (EGG) is a recording of the electric activity of the stomach as measured on the abdominal surface. In this study, our goal was to obtain a mathematical model of an EGG in the elderly. Subjects included 7 males and 7 females ranging from 65 to 76 years in age. Initially, we applied the Wayland algorithm to the EGG in order to measure the degree of determinism. However, we could not determine whether the EGG could be generated by a chaotic process. Incidentally, the waveform of the electric potential in the interstitial cells of Cajal is similar to the graphs generated from the numerical solutions of the Van der Pol equation. We therefore added the Van der Pol equation to a periodic function and used random white noise to represent the intestinal motility and other biosignals. We then compared and evaluated the EGG and numerical solutions on the basis of the translation error in the Wayland algorithm and the maximum Lyapunov exponent in Rosenstein’s algorithm. By projecting the data from stationary EGGs and the numerical solutions onto the Etrans–λ plane, we could qualitatively evaluate the affinity between them. In conclusion, a mathematical model of the EGG in the elderly includes stochastic differential equations that do not describe the stochastic resonance (SR). Conversely, the SR is statistically applicable to the mathematical model of the stationary EGG in the healthy young. In this paper, we also discuss the physical meaning of the mathematical model of EGGs in the elderly.

Index Terms—Electrogastrography, numerical solution, wayland algorithm, lyapunov exponent, stochastic resonance (SR).

H. Takada is with the Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo Fukui-City, Fukui 910-8507, Japan (e-mail: takada@u-fukui.ac.jp).
Y. Matsuura is with the Headquarters for Innovative Society-Academia Cooperation, University of Fukui, 3-9-1 Bunkyo Fukui-City, Fukui 910-8507, Japan (phone: +81-776-27-8795; fax: +81-776-27-8420; e-mail: matuura@u-fukui,ac.jp)
M. Miyao is with the Graduate School of Information Science, Nagoya University, Furo-cho Chikusa-ku Nagoya, Aichi 464-8603, Japan (e-mail: mmiyao@is.nagoya-u.ac.jp).

Cite: Hiroki Takada, Yasuyuki Matsuura, and Masaru Miyao, "Numerical Analysis of Electrogastrogram in the Elderly," International Journal of Bioscience, Biochemistry and Bioinformatics vol. 2, no. 6, pp. 403-406, 2012.