Abstract
OBJECTIVES: This short report relied on multiyear data from the National Alzheimer's Coordinating Center - Uniform Data Set (NACC-UDS) to examine whether significant changes occurred in functional status, neuropsychiatric symptoms, and depressive symptoms in the years before receiving an Alzheimer's disease (AD) diagnosis. METHOD: The secondary analysis used a retrospective cohort design. The NACC-UDS is a publicly accessible, longitudinal database that includes standardized data on neuropsychiatric symptoms, functional status, and depressive symptoms for Alzheimer's Disease Center (ADC) participants in the USA based on their annual visits from 2005 to 2011. ADC participants were considered diagnosed with AD if a follow-up data form indicated an affirmative response to whether the ADC participant had 'probable AD (National Institute of Neurological and Communicative Disorders and Stroke (NINCDS)/Alzheimer's Disease and Related Disorders Association (ADRDA))' or 'possible AD (NINCDS/ADRDA).' This yielded an analytic sample of 2478 individuals (139 with an eventual probable AD diagnosis, 109 individuals with an eventual possible AD diagnosis, and 2230 without any AD diagnosis) representing a total of 11,358 visits/points of data. RESULTS: Multilevel linear models revealed significant decreases (p < 0.05) in functional status prior to a probable or possible AD diagnosis and significant increases in depressive symptoms prior to a probable AD diagnosis. DISCUSSION: Changes in functional and depressive symptoms were partly independent of cognitive decline. The longitudinal results lend additional support to conceptual and empirical models of pre-diagnosis declines in AD.