Phenotyping Apathy in Individuals With Alzheimer Disease Using Functional Principal Component Analysis

• Published in: The American journal of geriatric psychiatry Vol. 21; no. 4; pp. 391 - 397
• Main Authors: Zeitzer, Jamie M., Ph.D, David, Renaud, M.D, Friedman, Leah, Ph.D, Mulin, Emmanuel, M.D, Garcia, René, Ph.D, Wang, Jia, M.S, Yesavage, Jerome A., M.D, Robert, Philippe H., M.D, Shannon, William, Ph.D
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.04.2013; Elsevier Limited
• Subjects: Actigraphy; Aged; Aged, 80 and over; Alzheimer disease; Alzheimer Disease - complications; Alzheimer Disease - physiopathology; Alzheimer Disease - psychology; Apathy; circadian; Circadian Rhythm - physiology; Depression - complications; Depression - physiopathology; Depression - psychology; Female; functional data analysis; Humans; Internal Medicine; Male; Motor Activity - physiology; Principal Component Analysis; Sleep; sleep; functional data analysis; circadian; actigraphy; Alzheimer disease; apathy
• ISSN: 1064-7481; 1545-7214
• DOI: 10.1016/j.jagp.2012.12.012

Objectives To determine if there is a specific pattern of gross motor activity associated with apathy in individuals with Alzheimer disease (AD). Design Examination of ad libitum 24-hour ambulatory gross motor activity patterns. Setting Community-dwelling, outpatient. Participants Ninety-two individuals with AD, 35 of whom had apathy. Measurements Wrist actigraphy data were collected and examined using functional principal component analysis (fPCA). Results Individuals with apathy have a different pattern of gross motor activity than those without apathy (first fPCA component, p <0.0001, t = 5.73, df = 90, t test) such that there is a pronounced decline in early afternoon activity in those with apathy. This change in activity is independent of depression (p = 0.68, F[1, 89]  = 0.05, analysis of variance). The decline in activity is consistent with an increase in napping. Those with apathy also have an early wake and bedtime (second fPCA component, t = 2.53, df = 90, p <0.05, t test). Conclusions There is a signature activity pattern in individuals with apathy and AD that is distinct from those without apathy and those with depression. Actigraphy may be a useful adjunctive measurement in the clinical diagnosis of apathy in the context of AD.