Plasma Alzheimer’s disease biomarkers and intraindividual cognitive variability measured by ecological momentary assessment in adults with type 1 diabetes

Abstract

AbstractBackgroundOlder adults with type 1 diabetes (T1D) have elevated risk of Alzheimer’s disease and related dementias (ADRD) compared to non‐diabetic controls. Because of oscillations in blood glucose, individuals with T1D are also prone to physiological and cognitive fluctuations. Intraindividual cognitive variability (IICV), or within‐person standard deviation across cognitive tests, has been proposed as an alternative marker of early dementia. The aim of this study was to characterize the relationships between ADRD plasma biomarkers and IICV in adults with T1D via ecological momentary assessment (EMA) of cognition during regular daily activities.MethodAdults with T1D (age range 19‐84 yrs, mean = 48.9) who participated in the Glycemic Variability and Fluctuations in Cognitive Status in Adults with Type 1 Diabetes (GluCog) study and had available data on plasma β‐amyloid42/40, ptau181, NfL and GFAP levels measured using Quanterix assays were included in these analyses (N = 114). Cognition was assessed three times per day for 15 days. Within‐person measures of IICV were computed for each cognitive test after accounting for practice effects using multilevel modeling: Digit Symbol Matching reaction time (DSM‐RT; processing speed), Gradual Onset Continuous Performance Test d‐prime (GradCPT; cognitive control, attention), and Multiple Object Tracking accuracy (MOT; visual working memory). Multilinear regression models estimated associations between IICV and blood biomarkers, controlling for age, sex, education, person‐level mean cognition, and glucose variability (measured via continuous glucose monitoring).ResultsPTau181 and NfL were associated with IICV‐DSM‐RT (p<0.05). GFAP and β‐amyloid42/40 were not associated with any of the measures of cognitive variability investigated.ConclusionThese findings suggest that pTau181 and NfL are associated with cognitive variability measured via EMA in an adult sample at risk for ADRD. This is the first study to (i) investigate the association between plasma biomarkers of dementia and IICV measured via EMA and (ii) report plasma biomarker results in individuals with T1D. The results encourage future studies investigating diabetes‐related factors that may contribute to increased dementia risk.