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Effect of electrode contact area on the information content of the recorded electrogastrograms: An analysis based on Rényi entropy and Teager-Kaiser Energy

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Alagumariappan P. , Krishnamurthy K. , Kandiah S. , Ponnuswamy M. J.

Polish Journal of Medical Physics and Engineering

2017

tom Vol. 23, Iss. 2

37--42

Electrogastrograms (EGG) are electrical signals originating from the digestive system, which are closely correlated with its mechanical activity. Electrogastrography is an efficient non-invasive method for examining the physiological and pathological states of the human digestive system. There are several factors such as fat conductivity, abdominal thickness, change in electrode surface area etc, which affects the quality of the recorded EGG signals. In this work, the effect of variations in the contact area of surface electrodes on the information content of the measured electrogastrograms is analyzed using Rényi entropy and Teager-Kaiser Energy (TKE). Two different circular cutaneous electrodes with approximate contact areas of 201.14 mm2 and 283.64 mm2, have been adopted and EGG signals were acquired using the standard three electrode protocol. Further, the information content of the measured EGG signals were analyzed using the computed values of entropy and energy. Results demonstrate that the information content of the measured EGG signals increases by 6.72% for an increase in the contact area of the surface electrode by 29.09%. Further, it was observed that the average energy increases with increase in the contact surface area. This work appears to be of high clinical significance since the accurate measurement of EGG signals without loss in its information content, is highly useful for the design of diagnostic assistance tools for automated diagnosis and mass screening of digestive disorders.

Układ do pomiaru biopotencjałów mięśniowych wykorzystywanych w systemach sterowania

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Garstka T.

Pomiary Automatyka Kontrola

2012

tom R. 58, nr 4

348-351

W artykule przedstawiono budowę i parametry, opracowanego w Zakładzie Automatyzacji Procesów Przemysłowych Politechniki Częstochowskiej, układu służącego do pomiaru biopotencjałów mięśniowych, składającego się z elektrod pomiarowych, wzmacniacza, filtrów oraz układu przetwarzania. Oprócz charakterystyki i parametrów samego toru pomiarowego, przedstawiono również zarejestrowane, przykładowe przebiegi, odpowiadające wybranym stanom napięcia mięśnia kończyny górnej. Zebrane doświadczenia posłużyły do opracowania dwustanowego systemu sterowania, kontrolowanego biopotencjałem mięśniowym.

Biopotentials of muscles (Fig. 1) are widely used in electrodiagnostics of a human neuromuscular system. They can be also used for steering and control applications of processes. (Sections 1 and 2). The acquisition and processing of these biosignals require a special measurement system. This paper presents design and characteristics of the elaborated measurement channel (Section 3) consisting of circuits containing an amplifier, filters and envelope detector as well as a block of pulse forming for control application (Fig. 2). With use of this system, the samples waveforms of biopotentials corresponding to selected states of the arm biceps muscle tension (Fig. 4) were recorded. Based on the analysis of the obtained wave-form amplitude (Section 4, Fig. 5), the quick movement of the hand (Fig. 6) was selected for digital steering of a bistable switch (Section 5). By this strategy, the laboratory device safety switch was controlled on a satisfactory level. The general conclusion is that muscle biopotentials can be alternative to manual systems of steering ma-chines by buttons and switches (Section 6).