CONTINUOUS WAVELET ANALYSIS AS AN AID IN THE REPRESENTATION AND INTERPRETATION OF ELECTROGASTROGRAPHIC SIGNALS

This paper presents an application of the continuous wavelet transform (CWT) in the analysis of electrogastrographic (EGG) signals. Due to t he nonstationary nature of EGG signals, the CWT method, which uses mul tiresolution scaled windows, gives a better time-frequency resolution than the short-time Fourier transform, which uses a fixed window. Spik e activity due to gastric contraction was investigated through experim ents on dogs. During spike activity we observed an increase in magnitu de of the slow wave and the appearance of a low frequency component wi th half the frequency of the slow wave. Studies of the EGG signals fro m the small intestine are also presented to investigate the hypothesis that its slow wave might be confounded with spike activity in the sto mach due to the similarity of their frequency ranges. (C) 1998 Biomedi cal Engineering Society. [S0090-6964(98)00106-4].