The Relationship Between Gait Task Performance and Plasma Biomarkers for Alzheimer’s Disease in Cognitively Unimpaired Older Adults and Patients with Mild Cognitive Impairment

Purpose: The Timed Up and Go (TUG) is a 20-foot gait assessment, with TUG-dual task (DT) serial subtractions to determine dual-task cost. Alzheimer's disease (AD) risk is established using plasma biomarkers and APOE genotyping. Methods: We investigated: 1) TUG/TUG-DT differences between AD low-risk cognitively unimpaired (CU) older adults (N = 74), AD high-risk CU older adults (N = 87), and mild cognitively impaired (MCI) older adults (N = 33) and 2) the relationship between TUG/TUG-DT performance and plasma biomarkers. One hundred and ninety-four older adults ages 55-80 completed TUG/TUG-DT, a fasting blood draw, and APOE genotyping. Scores on the Clinical Dementia Rating Scale (CU = 0; CI = ≥0.5) and Montreal Cognitive Assessment (CU ≥ 24; CI = ≤23) determined whether participants were placed into the CU low-risk, CU high-risk, or MCI groups. Risk level for CU participants were assessed by APOE genotyping. Those participants who carried at least one copy of the APOE ε4 allele were designated to the high-risk group (n = 87). Participants with no APOE ε4 allele were assigned to the low-risk group (n = 75). Results: