Design and testing of a 6-component ballistocardiographic bed

Ballistocardiography is a non-invasive technique for the assessment of the cardiac function. It consists in studying the resultant forces generated by the blood mass flowing in the cardio-circulatory system while the subject lies on an instrumented bed. In the past, ballistocardiography was in large part limited by the signal processing and data acquisition capabilities. Technology improvements have countered these limitations. Previous studies by the authors using a regular size force plate have shown the capability of detecting cardiac activity in the human body. However, many patients with severe disorders cannot stand on a force plate for the duration required to acquire adequate data. Thus, a force plate, which performs as a ballistocardiographic bed, would allow patients to lie down in a stable position while body tremor data are acquired. To evaluate this idea, a highly sensitive ballistocardiographic bed was built using strain gage technology. Then, using high-resolution data acquisition software, the sensitivity of the instrument and the capability to obtain ballistocardiographic data were tested. Future developments include the analysis of ballistocardiographic data obtained from the bed to search their possible relation with cardio-circulatory and neurologic pathologies.