Fundamental Experiments on the Detection of Decubital Movement Using Piezoelectric Film

Abstract

Monitoring system is very important technique for the careful management of the condition of patients. Most of the system measures the quantitative information, such as cardiograph, blood pressure and so on. However, the qualitative monitoring including a decubital body motion also gives an important information. In this study, the living information of patients lying on the bed is measured. The direction of patient's body motion is the subject of analysis, and the method for automated recognition of the direction of body motion is suggested. In the experiments, the body motion was detected by the monitoring system as the electrical signal using the PVDF piezoelectric film sensors. The signal from the sensor was transformed into three levels digital signal having zero, +1 and -1 to discriminate the kind of body motion. As the result of experiments, the suggested method successfully discriminates between the longitudinal and transversal direction of body motion on the ordinary bed.