The goal of this RFA is to enable partnerships between academics and companies that make wearable devices to validate their digital health technologies (DHTs) as digital monitoring biomarkers in ADRD populations. Applications will be required to optimize their DHTs in diverse patient populations from two or more early stage clinically diagnosed ADRD. Studies must demonstrate the accuracy of the digital markers to differentiate clinically meaningful features (such as sleep stage) and establish the longitudinal relationship between the features measured with quality-of-life metrics. Studies should also establish the relationship with one or more analytically validated ADRD biomarker(s) and standard cognitive assessments to validate the relationship between the features measured by the DHTs with the underlying pathophysiology or cognitive concept it reflects. An ideal outcome would be evidence for incorporating these DHT measures as monitoring biomarkers in future ADRD clinical trials. A 5-year phased mechanism is requested with a 2-year start-up phase (R61) to ensure adequate community engagement and recruitment of diverse patient populations, and to conduct pilot studies to optimize the algorithms; this will be followed by a 3-year R33 validation phase.