MİDE TEMBELLİĞİ İÇİN ELEKTROGASTROGRAFİ (EGG) VE İŞLEVSEL ELEKTRİK UYARIM (İEU) SİSTEMİ TASARIMI
Özet
Gastroparesis is a condition of delayed gastric emptying that occurs as a result of slowing or stopping stomach movements known as stomach paralysis. Today, due to the rapidly developing technology, the use of electronic infrastructures in the field of health has become widespread. Electrogastrography (EGG) is the recording of the electrical activity of the patient's abdomen with the aid of surface electrodes placed in the abdominal skin. Due to simplicity, the non-invasive EGG method is more common. Nowadays, the EGG method can only be performed in certain private centers due to the hardware cost and the difficulties in reading and understanding the signals for which expertise are required. Recorded data can help diagnose diseases and speed up the treatment process. The Functional Electrical Stimulation (FES) system is a system that provides constant contraction of the stomach muscles by applying constant currents with surface electrodes to regulate slowing or accelerating stomach movements. Functional electrical stimulation is a new treatment method in the treatment of gastroparesis according to other methods.
In this thesis, through EGG method, one will be able to interpret the stomach signals which are very low in amplitude compared to other body signals with signal processing techniques and filters. Since the periods of the stomach signals are very long, many datas are required in the time domain. The examination of such a large number of intervals also causes loss of sensitivity in the information to be obtained. For this reason, the frequency domain techniques have been applied in signal analysis stage. The filtered signals were implemented in the hardware level and the electrical signals were triggered at appropriate times and levels to regulate digestive movements.
Stomach signals have very low amplitude and frequency due to their nature. For this reason, when standard signal processing techniques are applied due to both the deterioration in amplitude due to the noise from the body and the low frequency and the other noise sources, it is the main signal processing difficulties that the time-frequency resolution is not sufficient enough to obtain detailed information.
When the Fourier transform is applied to stomach signals with a long period, the frequency information contained in the signal is information that includes the all frequency spectrum spanning all time domain signal length. This information is also insufficient for sensitive decision making for short time variations in time domain signal stream. When the Short-Time Fourier Transform is applied, the time-frequency resolution needs to be adjusted properly. This tradeoff is practically problematic because the bandwidth of the signal examined is very small in the frequency domain. When the signal is analyzed by means of the method of correlation theory, the information obtained is also stated in the time domain. In addition to the time domain variations, the frequency information is also expected so that a proper and reliable treatment can be performed if the abnormality is detected. For this reason alone the method of correlation also remains inadequate.
There is insufficient information from sources of morphologies of stomach signals. Within the scope of the thesis, it is aimed to try to obtain a person specific stomach signal template by using dynamic template finding algorithm and to obtain detailed information by using it again while examining the stomach signal of the obtained template signal. When applying the dynamic template finding algorithm, the information obtained from the previous step of each step and to find the dominant frequency of the patient's stomach signal defining the closest gastroparesis time domain attributes during the contraction detection procedure is used. The most important feature of the dynamic template application is that it provides to find information in real time intervals while using the stomach signal and to use it more appropriate instants in the treatment phase.
As a result of these operations, diagnosis and treatment are combined so that the diagnosis of gastroparesis patients is facilitated together with the combined treatment method.
