An Application of Wavelet Transform (WT) and Independent Component Analysis (ICA) for Electrogastrographic (EGG) Signals Artifacts Detection

Electrogarstrogram (EGG) is an electric signal that is propagated through the muscles of stomach controlling muscles contractions and measuring stomach nerve activity before and after food ingestion. It is easy to perform, noninvasive and relatively inexpensive test which therefore has become an attractive method for physiologic and pathophysiologic examinations of the stomach. The main component of gastric myoelectrical activity, called gastric slow waves, has a frequency about 3 cycles/min (0.05 Hz). As a result the EGG signal requires longer recording time (usually more than 1 hour). Furthermore EGG is a weaker signal then other bioelectric signals, such as ECG or respiratory noise, so the EGG is usually contaminated by artifacts, which damage the recorded data and make analysis very difficult or impossible. In order to use EGG as diagnostic tool the artifacts have to be first detected and then automatically eliminated before the analysis starts.