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Dissertation
Continuous wavelet analysis as an aid in the representation and interpretation of electrogastrographic signals
Doctor of Philosophy (Ph.D.), Drexel University
1997
DOI:
https://doi.org/10.17918/00007516
Abstract
This dissertation is an investigation on the application of Continuous Wavelet Transform (CWT) on gastric signals recorded from abdominal surface (EGG). EGG signal is by nature a non-stationary signal whose frequency, amplitude and wave shape vary from time to time under different physiological status. The usual method of Fourier analysis therefore can not effectively be used to analyze its frequency contents. The CWT method for EGG signal processing has been developed to achieve high temporal and frequency resolutions for the slow wave and many other high frequency components such as spikes which usually occur in brief duration. An Adaptive Tracking System (ATS) has been developed to track out the individual components in EGG signal such as slow wave, the low- and high-frequency components. The CWT method is then applied to the serosal signals for the frequency analysis of the serosal spikes from stomach and small intestine. All our results proved that the CWT is an appropriate tool for both abdominal and serosal signal in EGG study. The detection of the gastric contractions from EGG signal has also been studied in this dissertation. We have found that the occurring gastric contractions change the characteristics of EGG signal. The characteristic changes in EGG signal as related to the gastric contractions, including the increase of the amplitude of slow waves and the appearances of the low- and high-frequency components, have been successfully detected by the CWT method. An analysis to verify the increase of the amplitude in stomach slow wave during contractions due to the presence of the second potentials in serosal signal is presented. Our study also shows that the high-frequency component of 10-15 cpm frequency might be contributed by the enhanced electric activities in small intestine and the serosal spikes in stomach during contractions. The low-frequency component whose frequency is about the half of the stomach slow wave or lower is directly related to the occurring gastric contractions but its origin needs further study.
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Details
- Title
- Continuous wavelet analysis as an aid in the representation and interpretation of electrogastrographic signals
- Creators
- Wenwei Qiao
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xvi, 194 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Drexel University
- Other Identifier
- 991021889069504721