Strategy Use on Digital Cognitive Assessment Differs Between Individuals with and without Elevated Phosphorylated Tau 217 in Cognitively Normal Older Adults: Results from the BioFINDER‐Brown Study

Abstract Background New immunotherapies for Alzheimer’s Disease (AD) have shown promise in slowing disease progression and are most effective in the early stages of the disease. New, low‐cost methodologies are needed to detect early AD pathological change. Digital cognitive tools may represent a cost effective, efficient, and sensitive method to detect early AD‐related pathological change. The present analysis utilizes data from the BioFINDER‐Brown study to investigate whether individuals with and without elevated plasma phosphorylated tau‐ 217 (p‐tau 217 ) demonstrate differential performance on digital cognitive assessments of spatial working memory (SWM) and paired associates learning (PAL). Method 90 cognitively normal (CN; M MMSE = 29.00) older adults ( M age = 63.36, 72.2% female, 95.6% white, 5.6% Latinx) completed a blood draw to evaluate plasma p‐tau 217 and two brief tablet‐based digital cognitive assessments: SWM and PAL. as part of screening for the BioFINDER‐Brown study. Approximately 42% of the sample (n = 38) had elevated plasma p‐tau 217 . Independent samples t‐tests were used to determine whether performance on these measures differed between individuals with and without elevated p‐tau 217 . Lower scores on both measures are indicative of better performance. Result The total number of errors on the SWM was not found to differ between individuals with and without elevated plasma p‐tau 217 ( t (89) = ‐1.33, p = 0.093). However, differences in strategy use were found on the SWM task ( t (89) = ‐2.11, p = 0.019); Individuals with elevated p‐tau 217 had a less efficient strategy and required more trials to complete the task (M = 8.79 trials) than non‐elevated individuals (M = 7.65 trials). Group differences between those with and without elevated p‐tau 217 on the PAL task approached significance ( t (89) = 1.08, p = .075), with worse performance in those with elevated p‐tau 217 . Conclusion The preliminary findings suggest that group differences may exist for process scores (i.e., strategy use) but not overall performance on digital cognitive assessments between individuals with and without elevated plasma p‐tau 217 . Future research should evaluate 1) which digital assessments are most sensitive to AD‐related pathological change and 2) whether digital cognitive assessments can be used in conjunction with novel, affordable plasma biomarkers to improve early detection of AD.