Toward an Understanding of Healthy Cognitive Aging: The Importance of Lifestyle in Cognitive Reserve and the Scaffolding Theory of Aging and Cognition.

This article focuses on comparing two prominent theories of cognitive aging: the revised Scaffolding Theory of Aging and Cognition (STAC-r) and Cognitive Reserve (CR) theory, both of which aim to explain mechanisms underlying healthy cognitive aging and dementia risk. STAC-r offers a multifaceted framework incorporating both positive lifestyle factors ("neural resource enrichment") and adverse influences ("neural resource depletion"), linking brain structure and function to compensatory neural scaffolding. In contrast, CR emphasizes the accumulation of cognitive reserve through life experiences that enhance cognitive strategies and neural flexibility but lacks a clearly defined neural basis and does not explicitly address negative factors like depression. Both theories agree on the benefits of an engaged lifestyle and interventions for maintaining cognition, yet STAC-r may better capture the complexity of cognitive aging and predict the rate of decline, while CR provides a simpler model useful for designing interventions, particularly in dementia. The article highlights the need for further research to clarify the interplay of these models, their application to neurodegenerative diseases, and the timing and components of effective interventions.