MoMo: A Low-Cost, Non-Contact System for Monitoring Patient Movement on a Support Surface

Pressure injuries remain a common and costly complication for hospitalized patients with limited mobility. Current monitoring approaches\u2014such as manual repositioning schedules, smart mattresses or mattress covers, and video surveillance\u2014are either labor-intensive, expensive, intrusive, or have potential to alter the skin's microclimate to increase pressure injury risk. We developed a non-contact motion monitoring system using only six accelerometers (so anticipated to be much lower cost than mattress pads with thousands of sensors) mounted along the sides of a standard hospital mattress to detect participant movement via the Poisson Effect. Data from nine healthy participants performing standardized and natural movements were collected alongside commercial pressure mat data, wearable inertial measurement unit recordings, and video footage. We evaluated three time-series-based movement detection algorithms, achieving an average area under the curve of 0.859, 0.900, and 0.916, respectively. The best-performing method detected 80% of movements with a false positive rate of 5%. The system preserves participant privacy and is compatible with any bed, making it a promising tool for large-scale pressure injury prevention and real-time monitoring in clinical care.