Episodic memory boosting in older adults: exploring the association of encoding strategies and physical activity

Background: Contextual memory is susceptible to the effects of aging and its impairment compromises episodic memories and quality of life in older adults. Objective: Compare the effects of cognitive support on incidental contextual memory free recall and recognition with a naturalistic experimental paradigm and explore the association of encoding strategies and physical activity on memory improvement. Methods: Subjects (≥60 years, n = 52) were assigned to one of two encoding conditions for the contextual memory task: with or without an incidental associative instruction to encourage association of an item to its spatial context. Immediate free recall and recognition tests were run to assess the encoding instruction efficiency. The association of memory performance and physical activity was analyzed using the scores on the International Physical Activity Questionnaire (IPAQ) to subdivide each experimental group into Low IPAQ (below median) and High IPAQ (above median) subgroups. Results: The associative encoding instruction increased contextual memory free recall and recognition, with greater effects on free recall. The most robust associations between physical activity and contextual memory were also seen on free recall, in which higher levels of physical activity corresponded to increased baseline performance (non-associative encoding condition) and greater improvement of memory by the encoding support (associative encoding condition). Conclusion: Cognitive support at encoding can improve contextual memory free recall and recognition, suggesting they are prone to rehabilitation. Moreover, higher physical activity levels were positively associated with encoding strategies on contextual memory improvement, increasing the availability of latent process-based components of the cognitive reserve.