Late-life memory trajectories in relation to incident dementia and regional brain atrophy
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The trajectory, or slope, of cognitive decline may provide differentiation of older adults with and without incipient neurodegenerative disease. Cognitive aging phenotypes based on memory trajectories could be used as outcome measures for clinical trials or observational studies of risk and protective factors for dementia. This study used growth mixture modeling (GMM) to identify trajectory groups based on age- and education-corrected composite memory scores derived from immediate, delayed and recognition trials of the Selective Reminding Test. Participants included 2593 participants initially without dementia (mean age at entry = 76) in a community-based study of aging and dementia in northern Manhattan. Trajectory groups were compared on consensus diagnoses of dementia and structural MRI measures of hippocampal volume and entorhinal cortical thickness. Heterogeneity in memory trajectories allowed us to identify four groups: Stable-High (43.5 %), Stable-Low (17.1 %), Decliner (26.8 %), and Rapid Decliner (12.5 %). Decliners had more brain atrophy and higher rates of conversion to dementia. This study highlights the heterogeneity in cognitive aging and provides evidence that most elderly maintain memory function as they age. Associations with dementia and imaging measures validate subgroups of older adults identified with GMM based on their memory trajectories. Future research should use these memory trajectory phenotypes to determine whether dementia risk and protective factors differ for individuals following different memory trajectories.
KeywordsCognitive aging Alzheimer’s disease MRI
This study was funded with support from the National Institute on Aging (grant numbers AG047963, AG037212, AG034189, AG007232). The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication. On behalf of all authors, the corresponding author states that there is no conflict of interest.
Compliance with ethical standards
Conflicts of interest
All authors declare no conflict of interest.
All participants gave informed consent before entering the study. The study was approved by the Institutional Review Boards at Columbia University.
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