可攜式記錄系統- 胃電之應用

Abstract

表皮胃電圖(EGG)是一種經由表皮電極，對胃的電氣活動非侵入性的量測，是胃的活動力指標，通常用於有消化功能性障礙病人的診察。功能性障礙可能是胃部肌肉或是控制肌肉的神經異常，胃電記錄可以協助臨床醫師診察噁心或想吐等功能性疾病，為了進行胃電的研究，本論文設計了一組床邊胃電記錄系統與其擷取及分析程式。 攜帶型生理信號系統對陣發性或突發性症狀的偵測及診斷有其重要性，經由長時間以攜帶方式來記錄信號，臨床醫師和研究者將更有機會來記錄到這些急性症狀，基於床邊胃電記錄系統的設計經驗，本文也設計了兩款攜帶型胃電記錄器。第一組是以微控制器為主的模組式記錄器，並在其上建構了記錄胃電(EGG)、心電圖(ECG)、以及腦電圖(EEG)的子板，是一模組化多功能生理信號記錄器。第二組是利用數位錄音棒來進行胃電記錄，我們設計了一個小型的電路模組，要讓一般市面上的數位錄音棒，可以記錄極低頻的胃電信號。而這兩組記錄器的設計都是小型化且低耗電的設計，很適合進行長時間生理信號的攜帶式記錄。 本文並以床邊胃電記錄系統配合超音波影像探討在胃排空時胃電與其之關係。由超音波影像量測到胃的體積變化，可以觀察到胃的排空(體積由大變小)，而胃電的主頻率之功率變化和超音波影像一致，對胃排空有相同的變化趨勢。我們也使用床邊記錄系統，探討胃音和胃電的關係，從研究結果可以得知，在胃音發生時，胃電的主頻率將明顯降低而主頻率之功率則會有明顯的增加。

Cutaneous electrogastrogram (EGG) is the electrical activity of the stomach. It is a non-invasive measurement via cutaneous electrodes. EGG is considered to be a motility index to of the stomach. A recording of EGG is usually used when a patient is suspected of having a functional disorder. The functional disorder means that the muscles of the stomach or the nerves controlling the muscles do not work as they should be. The EGG can help clinicians to diagnose the cause of chronic nausea and vomiting they are functional disorder of the stomach. For studying EGG signal, an EGG bedside recording system in addition to the software for acquisition and analysis was created. Ambulatory recording systems for biomedical signals are very important in detecting and diagnosing paroxysmal attack or sudden onset of symptoms. With a long-term ambulatory recording of signals, researchers and clinicians could have more opportunities to investigate and analyse these acute symptoms. Based on the experiences of the bedside EGG recording system, two types of portable EGG recorders were designed in this thesis. First one was designed based on a microcontroller. This portable recorder is a modular design, which contains a motherboard and daughterboards for the recording of electrogastrogram (EGG), electrocardiogram (ECG), and electroencephalogram (EEG) signals. The second one was based on a digital voice recorder. A compact circuit was designed to make the commercial audio recording device being able to record the low frequency EGG. Both of them are compact dimension yet low power consumption. They are suitable for long-term portable recording of biomedical signals. Based on our bedside EGG system and the ultrasonic image of the stomach, the relationship between the emptying and the EGG was studied. The decrease in volume measured by the ultrasound showed the gastric emptying, while the power of the dominant frequency displayed the same trend as the ultrasonic measurement. We also use this system to study the relationship of gastric sound and EGG. The result showed that the dominant frequency decreased and the dominant power increased when the gastric sound appeared.