Multi-signal bathroom scale to assess long-term trends in cardiovascular parameters

This paper describes the circuits and signal processing techniques that convert an electronic bathroom scale intended for bioimpedance analysis (BIA) into a compact system to acquire the electrocardiogram (ECG), the ballistocardiogram (BCG), and the impedance plethysmogram (IPG) using only plantar measurements. The signal processing methods proposed rely on the higher quality of the IPG as compared to the ECG and BCG and they enhance the signal-to-noise ratio (SNR) of these two signals, which otherwise could be too poor in non-controlled environments. The system is suitable for long-term periodic monitoring of cardiovascular function.