Identification of the slow wave of bowel myoelectrical surface recording by empirical mode decomposition.

Surface electroenterogram (EEnG) is a non-invasive method to study bowel myoelectrical activity. Nevertheless, surface recorded EEnG is contaminated by respiratory, motion artifacts, and other interferences. The goal of this paper is to remove the respiration artifact and ultra-low frequency components from surface EEnG by means of empirical mode decomposition (EMD). Seven recording sessions on abdominal surface of three Beagle dogs were conducted. Power percentages of interferences and of fundamental slow wave were calculated before and after the application of the method. The results show that the interference power is significantly reduced (23 +/- 16% vs. 5 +/- 4%), and fundamental slow wave power is significantly increased (59 +/- 17% vs. 76 +/- 13%). Therefore, the EMD method can be helpful to remove respiration and ultra-low frequency components from the external EEnG recordings.