Denoising Motion-Corrupted Seismocardiogram Signals Using Score-Based Generative Diffusion Models

Noninvasive monitoring of hemodynamic parameters is essential for assessing cardiovascular function to enable early identification of high-risk individuals and help prevent injuries. However, current wearable solutions that use the electrocardiogram or photoplethysmogram offer a limited view of cardiovascular health, particularly in capturing cardiomechanical function. The seismocardiogram (SCG), a cardiomechanical signal, has shown promise in filling this gap with features previously shown to reflect key hemodynamic parameters. However, the SCG is susceptible to motion-artifacts, limiting its effectiveness in real-world settings where monitoring during physical activities or in hot environments is crucial due to the increased injury risk. In these environments, motion artifacts are variable and high in magnitude necessitating effective motion-artifact reduction algorithms. In this work, we propose a score-based generative diffusion model framework to obtain high quality SCG signals in daily-life environments. We leverage the periodicity of clean SCG beats to learn a probability space, which can be used as a prior to generate motion-free SCG signals from corrupted observations. Furthermore, generation quality is enhanced through a multi-generation averaging approach. Performance was analyzed on a waveform level and through feature extraction accuracy using a healthy dataset of participants undergoing exercises. We achieved mean absolute errors of 3.74 ms and 7.67 ms on two extracted SCG features: aortic valve opening (AO) and closing (AC), respectively, outperforming other signal processing and deep learning approaches from prior work. Furthermore, we demonstrated effective denoising capabilities on an unseen dataset collected in daily life settings, demonstrating the model's generalizability. Denoising systems such as this have the potential to be integrated into wearable systems, enabling reliable SCG signal acquisition for more accurate hemodynamic indices and reducing injuries in high-risk individuals.