Contactless under-mattress sensors successfully predicted next-day agitation episodes in dementia patients across 73 individuals and over 1,100 nights of monitoring. Lower nocturnal respiratory rates and greater sleep activity instability emerged as independent predictors, with stronger associations for motor versus verbal agitation behaviors. The respiratory markers validated across both institutional and home settings. This represents a significant advance in dementia care technology, where behavioral symptoms like agitation affect up to 90% of patients and impose enormous caregiver burden. Current clinical practice relies heavily on reactive management after episodes occur, but these findings suggest proactive intervention may become possible through continuous physiological monitoring. The contactless nature eliminates patient discomfort from wearables while providing objective risk assessment. However, the study found nocturnal signals couldn't predict agitation severity, only occurrence. The relatively small cohorts and observational design limit causal interpretations, and individual variability in dementia progression wasn't fully captured. As a preprint awaiting peer review, these promising results require validation through larger controlled studies before clinical implementation. The technology could transform dementia care from reactive to preventive, potentially reducing behavioral crises and improving quality of life.