Evaluating the Foot Electromyogram Signal as a Noise Reference for a Bathroom Scale Ballistocardiogram Recorder

A bathroom scale ballistocardiogram (BCG) recorder has been developed in our group as a potential home monitor for heart failure outpatients. While the signal quality obtained by this device is as high as elaborate table- and bed-based BCG systems discussed previously in the literature, the standing posture required by this system may lead to undesired motion induced noise in the signal, particularly for elderly patients. Electromyogram (EMG) signals from the feet are proposed as a noise reference for the standing BCG measurement. The correlation between these signals and the BCG noise is quantified for a case with low (eyes open) and higher (eyes closed) involuntary movement on the scale. For the six subjects considered in this trial, the foot EMG appears to be a valuable reference for BCG movement noise estimation. Additionally, the fact that many bathroom scales have electrodes on the feet for various body fat percentage estimates makes the measurement highly practical for future implementations.