Electrogastrographic examination (EGG) is a noninvasive method for an investigation\nof a stomach slow wave propagation. The typical range of frequency for EGG signal is\nfrom 0.015 to 0.15 Hz or (0.015ââ?¬â??0.3 Hz) and the signal usually is captured with sampling\nfrequency not exceeding 4 Hz. In this paper a new approach of method for recording\nthe EGG signals with high sampling frequency (200 Hz) is proposed. High sampling\nfrequency allows collection of signal, which includes not only EGG component but\nalso signal from other organs of the digestive system such as the duodenum, colon as\nwell as signal connected with respiratory movements and finally electrocardiographic\nsignal (ECG). The presented method allows improve the quality of analysis of EGG\nsignals by better suppress respiratory disturbance and extract new components from\nhigh sampling electrogastrographic signals (HSEGG) obtained from abdomen surface.\nThe source of the required new signal components can be inner organs such as the\nduodenum and colon. One of the main problems that appear during analysis the EGG\nsignals and extracting signal components from inner organs is how to suppress the\nrespiratory components. In this work an adaptive filtering method that requires a reference\nsignal is proposed. In the present research, the respiratory component is obtained\nfrom non standard ECG (NSECG) signal. For purposes of this paper non standard ECG\n(namely NSECG) is used, because ECG signal was recorded by other than the standard\nelectrodes placement on the surface of the abdomen. The electrocardiographic\nderived respiration signal (EDR) is extracted using the phenomena of QRS complexes\namplitude modulation by respiratory movements. The main idea of extracting the EDR\nsignal from electrocardiographic signal is to obtain the modulating signal. Adaptive\nfiltering is done in the discrete cosine transform domain. Next the resampled HSEGG\nsignal with attenuated respiratory components is low pass filtered and as a result the\nextended electro gastro graphic signals, included EGG signal and components from\nother inner organs of digestive system is obtained. One of additional features of the\nproposed method is a possibility to obtain simultaneously recorded signals, such as:\nnon-standard derivation of ECG, heart rate variability signal, respiratory signal, and EGG\nsignal that allow investigating mutual interferences among internal human systems.
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