Temporal dynamics of depressive symptoms and cognitive decline in the oldest old: dynamic time warp analysis of the Leiden 85-plus study

• Published in: Age and ageing Vol. 53; no. 7
• Main Authors: van der Slot, Abe J C, Bertens, Anne Suzanne, Trompet, Stella, Mooijaart, Simon P, Gussekloo, Jacobijn, van den Bos, Frederiek, Giltay, Erik J
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 02-07-2024; Oxford Publishing Limited (England)
• Subjects: Age Factors; Aged, 80 and over; Cognition; Cognitive ability; Cognitive Aging - psychology; Cognitive Dysfunction - diagnosis; Cognitive Dysfunction - epidemiology; Cognitive Dysfunction - psychology; Cognitive functioning; Cognitive impairment; Delayed; Depression - diagnosis; Depression - epidemiology; Depression - psychology; Education; Female; Geriatric Assessment - methods; Happiness; Higher education; Hopelessness; Humans; Life satisfaction; Male; Mental depression; Mental Status and Dementia Tests; Netherlands - epidemiology; Neuropsychological Tests; Prevalence; Research Paper; Risk Factors; Stroop task; Tests; Time Factors; Very old; Netherlands; time series; cognitive impairment; network analysis; older people; depression; oldest old
• ISSN: 0002-0729; 1468-2834; 1468-2834
• DOI: 10.1093/ageing/afae130

Abstract
Background
The prevalence of depressive symptoms and cognitive decline increases with age. We investigated their temporal dynamics in individuals aged 85 and older across a 5-year follow-up period.
Methods
Participants were selected from the Leiden 85-plus study and were eligible if at least three follow-up measurements were available (325 of 599 participants). Depressive symptoms were assessed at baseline and at yearly assessments during a follow-up period of up to 5 years, using the 15-item Geriatric Depression Scale (GDS-15). Cognitive decline was measured through various tests, including the Mini Mental State Exam, Stroop test, Letter Digit Coding test and immediate and delayed recall. A novel method, dynamic time warping analysis, was employed to model their temporal dynamics within individuals, in undirected and directed time-lag analyses, to ascertain whether depressive symptoms precede cognitive decline in group-level aggregated results or vice versa.
Results
The 325 participants were all 85 years of age at baseline; 68% were female, and 45% received intermediate to higher education. Depressive symptoms and cognitive functioning significantly covaried in time, and directed analyses showed that depressive symptoms preceded most of the constituents of cognitive impairment in the oldest old. Of the GDS-15 symptoms, those with the strongest outstrength, indicating changes in these symptoms preceded subsequent changes in other symptoms, were worthlessness, hopelessness, low happiness, dropping activities/interests, and low satisfaction with life (all P’s < 0.01).
Conclusion
Depressive symptoms preceded cognitive impairment in a population based sample of the oldest old.