1. Latent Variable Modeling of Neurocognitive Reserve Rich Jones for the Latent Variable Modeling of Reserve Friday Harbor Workgroup: Laura Gibbons, Leo Morales, Dorene Rentz, Karen Liu, Yaakov Stern, Janessa Carvalho, Jennifer Manly, Angela Jefferson 16 Feb 2010

2. Abstract Neurocognitive reserve, broadly conceived, encompasses aspects of brain structure and function that optimize individual performance in the presence of neuronal injury. Reserve is often studied in the context of progressive cognitive disorders of aging. In vivo measures of neuronal injury are not widely available in such contexts. Therefore, observational and clinical studies operationalize reserve with proxies such as level of educational, occupation, participation in daily activities that involve cognitive activity, and vocabulary tests. Given this wide array of variables used to represent cognitive reserve, questions of how to combine them, or to characterize dimensions of cognitive reserve, have arisen. Increasingly latent variable models are used to generate composites of cognitive reserve based on multiple proxies. In this paper we review the theoretical and ontological status of latent variable modeling approaches to neurocognitive reserve, and suggest research strategies for advancing the field. We illustrate analytic approaches and provide new results using data from the Memory and Aging Project, a prospective observational and clinicopathologic study of cognitive aging.

3. Paper Outline (2) 1.Introduction and Background a.Reserve broadly defined. b.Approaches to operationalizing reserve c.Proposed (ie, published) latent variable models of reserve d.Critique – from Latent Variable Theory 1)Formative vs. reflective measurement 2)Ontological positions 3)Primacy of reflective measurement e.Synthesis and Goals of this Paper

4. Paper Outline (2) 2.Analysis a.Reflective model of reserve (Figure 1) b.Formative model of reserve (Figure 2) c.Combined formative/reflective (Figure 3)

5. Paper Outline (3) 3.Summary ?? 4.Limitations – Other analysis perspectives and approaches (e.g., latent class analysis) – Limited inputs to complex behavior/trait – Not an operationalization of the conceptual definition of reserve (which requires moderation of pathology effect on performance) 5.Conclusions ??

6. Figure 1. Reflective model of reserve.

7. Figure 2. Formative model of reserve.

8. Figure 3. Combined formative and reflective measurement model of reserve.