Objectives: Episodic memory is typically declining in older age but some Superagers have high performance levels. A superager level of performance may be preceded by different trajectories. The purpose of this study was to use longitudinal data to assign Superagers to stable or declining trajectories and then consider variation in memory trajectories in analyses of predictors of Superaging.
Methods: In the longitudinal Betula study we identified 139 Superagers (Mean age=79 years) with as good or higher episodic memory as the average of 300 50–60 years old individuals. Episodic-memory trajectories of 125 Superagers were defined from up to 25 years of longitudinal data. The Betula database provided information on possible predictors of Superaging, including education, cognition, polygenic scores, health, lifestyle, and structural brain integrity.
Results: The majority of Superagers were on stable trajectories from initially high to average levels, but some were on declining trajectories from high levels. Similar longitudinal profiles were seen on a word-fluency task. Analyses of predictors of Superaging revealed that education and a polygenic score for cognition were related to initial memory level, and that a polygenic score for dementia was related to rate of change. Most but not all superagers with high-stable memory had favorable education and polygenic predictor scores, suggesting alternative pathways to Superaging. Longitudinal imaging data revealed less atrophy in entorhinal cortex and hippocampus for Superagers.
Conclusion: A superager performance level can reflect well-maintained memory or decline from high initial levels, with distinct factors explaining variability in initial level or stability over time. Medial-temporal lobe brain maintenance characterizes episodic-memory Superagers.