Abstract Dementia research has focused almost exclusively on the deleterious aspects of AD, including memory loss, cerebral atrophy, and the molecular consequences of Aβ/tau pathology. Unfortunately, despite advances in our understanding of AD, the toolbox of viable treatments is no greater today than 20 years ago. An astonishing, yet underappreciated, aspect of AD/ADRD is the moment-to-moment fluctuation in cognitive health. Cognitive fluctuations, defined as spontaneous alterations in attention, arousal, and cognition, are evaluated based on the occurrence of symptoms such as impaired consciousness or confusion. However, the exact features and causes of cognitive fluctuations are still unclear. A greater understanding of the factors that lead to cognitive fluctuations and the precise behaviors that are present would allow us to identify strategies for preventing and managing dementia symptoms. We plan to provide a robust framework for quantifying cognitive fluctuations and lucid intervals in individuals with Alzheimer’s disease (AD) using a mobile technology platform applied within one’s home or local environment. Psychometric test results collected using a diagnostic app will be integrated with caregiver reports of cognitive changes to determine the features and incidence of these moments in AD patients (Aim 1). We then aim to identify reliable predictors of cognitive fluctuations and lucid intervals using wearable health sensors to uncover data-driven patterns of cognitive change (Aim 2). This three-dimensional view of cognition (in-home cognitive testing, caregiver reports, health sensors) will provide unprecedented insight into the nature of cognitive decline, cognitive fluctuations, and potentially incidences of lucidity.