An epidemiological approach to cognitive health in aging
The purpose of this chapter is to explore the foundations and implications of an epidemiological approach to understanding the multiple change trajectories and outcome patterns in the ﬁeld of cognitive aging. Whereas it is reasonably apparent that there are multiple trajectories of cognitive changes with aging (ranging, in principle, from gains to losses), there is a correspondingly large range of functional outcomes of these trajectories (ranging, colloquially, from successful to normal to pathological cognitive aging). Well known, as well, is the fact that these trajectories and outcomes are often multiply-determined, with inﬂuential precursors, moderators, and mediators originating in levels of analyses from the neurobiological to the cognitive and to the sociocultural (Cabeza, Nyberg, & Park, 2004; Dixon, Bäckman, & Nilsson, 2004; Hess & Blanchard-Fields, 1999; Park, Nisbett, & Hedden, 1999). The present goal is to explore the development of a framework for considering multiple precursors, proﬁles, and patterns of cognitive health in aging. The framework is broadly epidemiological and includes both theoretical and methodological implications, but this is not primarily a theoretical or a methodological chapter. Rather, the focus is on exploring and illustrating the concept of cognitive health and how it can be approached in an epidemiological framework.