Amyloid accumulation associated with worse performance of complex task

Background The preclinical stage of Alzheimer disease (AD) is largely considered a clinically silent period that is detectable primarily through neuroimaging and biofluid biomarkers of amyloid and tau. We evaluated whether performance of complex daily activities is associated with amyloid accumulation as measured by positron emission tomography (PET) among cognitively normal (CN) individuals with or without preclinical AD. Method CN participants (Clinical Dementia Rating 0) from the Knight Alzheimer Disease Research Center performed three activity subtasks (shopping, checkbook balancing, and medication management) from the Performance Assessment of Self‐Care Skills (PASS) at their homes. They also had an amyloid PET scan using Pittsburgh Compound‐B within one year of completing the PASS. PASS subtasks were scored for independence, adequacy, and safety of performance. Nonparametric correlations were used to determine the associations between amyloid accumulation and performance on each subtask. Result Fifty‐six CN participants (mean age 74.8 years, 61% female, 87% white) were included. Median amyloid PET was 1.17 (interquartile range 1.07–1.63; standard cutoff for preclinical AD: 1.42). Amyloid PET accumulation was not associated with performance on the checkbook balancing or medication management subtasks of the PASS. Higher amyloid PET accumulation was associated with worse performance on the shopping subtask of the PASS. Conclusion This study suggests that a complex task, measured using a performance‐based test, may be associated with higher amyloid deposition. Performance‐based measures could potentially serve as a less expensive method for screening individuals who may likely benefit from further evaluation (plasma amyloid or PET amyloid). They could also lead to a better understanding of functional changes that may be occurring during the preclinical stage of AD.