PROJECT SUMMARY/ABSTRACT Type 1 diabetes (T1D) is one of the most common chronic childhood diseases and has a rapidly rising incidence and prevalence. Management of blood glucose is challenging and often leads to frequent and rapid swings between normal, high, and low glucose. This glucose variability has recently been identified as an independent risk factor for diabetic complications. One of the least studied and understood complications of T1D is altered cognition and its relationship to glucose variability. As the brain uses a substantial amount of the body’s glucose to support its functions, especially during dynamic periods of brain development, there are strong biological reasons for the potential vulnerability of youth with T1D. Several studies have shown lower cognitive scores in youth with T1D compared to their peers without T1D, and shown that poorer overall glycemic control as indicated by severe glycemic events (e.g., diabetic ketoacidosis) and chronic hyperglycemia, are associated with lower cognitive scores both acutely and long-term. However, these studies we conducted in a controlled, optimized laboratory settings at a single time point. Little is still known about how typical glucose fluctuations that occur daily in real-life settings affect cognitive function in the moment, particularly dynamic cognitive skills that are sensitive to environmental or physical conditions of the individual (e.g. sleep deprivation) and thus fluctuate throughout the day (e.g., working memory, processing speed). Determining the relationship between glycemic fluctuations and dynamic cognitive function is critically important in youth given that dynamic cognitive skills are fundamental for learning, integrating, and using novel information in their daily lives. Understanding how these skills are affected in daily life, how they relate to glycemic fluctuations, and any contributing factors, could motivate improvements in academic accommodations and T1D treatment recommendations. Importantly, this work could also be expanded to better understand the impact of glycemic variability on brain health throughout the lifespan in T1D and could be translated to other forms of diabetes (e.g., type 2 diabetes, gestational diabetes). The primary goal of this study is to determine if real-time, real-life glycemic variability predicts fluctuations in dynamic cognitive function in youth with T1D. A secondary goal is to determine whether dynamic cognitive function in youth with T1D differs from youth without T1D, independent of significant glycemic extremes. To address these questions, I will apply a unique and innovative combination of continuous health and cognitive data collection methods, multivariate time-series analyses, and machine learning models. This work, combined with a tailored career development plan, will form the basis of my future work as an independent investigator, which will expand to address how diabetes-related health behaviors (e.g., food choice) ...