Stimulus artifact cancellation in the serosal recordings of gastric myoelectric activity using wavelet transform

Abstract

Previous studies have shown that electrical stimulation of the stomach (i.e., gastric pacing) with appropriate parameters is a promising method for treatment of gastroparetic patients. The recording of gastric myoelectric activity (GMA) by serosal electrodes is often used to evaluate the effect of stimulation. However, the major problem with the measurement of GMA during gastric pacing is the stimulus artifacts which are often superimposed on the serosal recording and make analysis difficult. The frequency-domain adaptive filter has been used to reduce the stimulus artifacts but only with limited success. This paper describes a wavelet transform-based method for the reduction of stimulus artifacts in the serosal recordings of GMA. The key of this method lies in the use of the fuzzy set theory to select the stimulus artifact-related modulus maxima in the wavelet domain. Both quantitative and qualitative measures show that significant stimulus artifact cancellation was achieved through a series of computer simulations. Results from both single- and multichannel serosally recorded myoelectric signals during gastric pacing are presented to demonstrate the efficiency of the proposed method for the cancellation of stimulus artifacts.

Wavelet analysis in a canine model of gastric electrical uncoupling

“…Separately, refined signal processing techniques, such as wavelets, have been employed to analyse electrogastrograms (Xie and Sun 1998, Ryu et al 2000, Liang et al 1996, Liang and Lin 2002, Qiao et al 1996. This approach has been used to (i) propose new wavelets that can offer a better time-frequency localization of EGG signals (Xie andSun 1998, Ryu et al 2000); (ii) perform noise detection in EGG recordings (Liang et al 1996); (iii) reduce stimulus artefacts (Liang and Lin 2002); and (iv) characterize global gastric electrical dysrhythmias (Qiao et al 1996).…”