Sources of resilience against neurodegenerative diseases, such as cognitive reserve, have been identified as modifiable factors that can prevent the manifestation of clinical dementia. A recent trend in dementia research has employed the concepts of reserve and resilience in the context of a lifespan to develop a life course approach, which integrates the risks of dementia and provides prevention strategies throughout life. This chapter introduces the life course approach to understanding dementia, which is a scientific discipline based on the span of life involving biology, psychology, and the social sciences in a single integrated causal structure to provide a framework to organize the multifactorial process involved in human aging and dementia. The cognitive reserve hypothesis and essential studies validating the theory are introduced; these report the moderating effects of literacy and formal education in dementia manifestation. Brain maintenance, another important component in understanding the resistance to brain aging and neurodegenerative diseases, is also discussed. Lastly, the chapter proposes a hypothetical pathway model to help understand the complex interaction between social relation and brain aging underlying the moderation that could either reduce or increase the risks of dementia.

The concept of cognitive reserve was proposed to account for the discrepancy between clinical outcomes and the extent of age-related brain changes, neuropathology, or brain damage. This chapter reviews the concept of cognitive reserve, the methods used to characterize it, and theoretical issues concerning its measurement and utilization. We begin with an overview of the concept of cognitive reserve, how it is distinguished from brain reserve, and how it is defined in current literature. We then explore both epidemiological and neuroimaging evidence supporting the concept of cognitive reserve and review how novel neuroimaging tools are contributing toward our understanding of the mechanisms by which cognitive reserve may operate. We conclude by addressing the future of cognitive reserve and its implications for the field of cognitive aging as a whole.