Clinical Manifestations.

Abstract

The preclinical stage of Alzheimer disease (AD) is a clinically silent period that is detectable through neuroimaging and biofluid biomarkers of amyloid, tau, and neurodegeneration. We evaluated whether performance on cognitively-focused complex daily tasks is associated with cerebrospinal fluid (CSF) biomarkers of brain amyloidosis or tau pathology in cognitively normal (CN) older adults. In this cross-sectional analysis of an ongoing longitudinal cohort study, CN older adults performed three cognitively-focused complex tasks of daily living (shopping, checkbook balancing, and medication management) from the Performance Assessment of Self-Care Skills (PASS) in their home. PASS tasks were scored for independence (cues required to complete task) and adequacy of performance (quality and process, efficiency, redundant actions). Participants also had a CSF sample obtained within two years of completing the PASS. CSF amyloid (Aβ42, Aβ40) and CSF tau phosphorylated at position 181 (p-tau181) were measured with Lumipulse immunoassays. Nonparametric partial correlations were used to examine the associations between task performance and biomarkers of AD (CSF Aβ42/Aβ40 and CSF p-tau181), controlling for age, gender, and level of education. 122 CN participants (mean age 74.4 years, 53% female, 88% white) were included. After controlling for age, gender, and years of education, worse performance on complex daily tasks was associated with lower CSF Aβ42/Aβ40 (more cues required: Spearman rho = -0.213, p = 0.03), and there was a trend towards lower adequacy (rho = 0.161, p = 0.08). There were no significant associations with CSF p-tau181. This study suggests that worse performance on complex daily tasks in CN older adults may be associated with greater amyloid burden. These findings could lead to a better understanding of functional changes that may be associated with amyloidosis prior to the onset of noticeable memory symptoms in AD or related dementias.