Dynamic Changes in Cognitive Activity and Global Cognition in the Memory and Aging Project Members (in alphabetical order): Amber, David, Doug, Emily, Frances, Joey, Kim, Gerald, Rich Presenter: Frances

Purpose To identify whether cognitive activity is a leading or lagging indicator for global cognition. Hypothesis: Cognitive activity will be a leading indicator for global cognition; higher cognitive activity will predict reduced global cognitive decline over time.

∆∆ ∆ ∆ ∆∆ Current cognitive Activity Cognitive Performance CA1 CA2 CA3CA4 CP1 CP2 CP3 CP4 int slope 11 1 time1time2time3time4 time1time2time3time4 Bivariate Dual Change Score Model

Methods Sample –990 participants who had baseline global cognition score, at least five cognitive activities completed, and no dementia.

Measures The following were rescaled from to be on the same scale: –Global cognitive score Based on 19 tests from the following domains: episodic memory, semantic memory, working memory, perceptual speed, and visuospatial ability –Cognitive activities Based on playing games, writing letters, reading books, magazine, and newspaper Age: Centered at 75 years old at baseline and standardized as a continuous variable

Statistical Analysis Bivariate Dual Change Score Models Mplus v.5.2 Stata v.10

Results

Description of Global Cognition and Cognitive Activities over 7 Waves

Individual and Mean Trajectories for Cognitive Activity and Global Cognition

Global Cognition Dual Change Score Model

Cognitive Activities Dual Change Score Model

Bivariate Dual Change Score Model for Global Cognition and Cognitive Activities *All models exclude the proportional change parameter for cognitive activities. No effect of activity on cognition No effect of cognition on activity

∆y∆ ∆ ∆ ∆∆x Current cognitive Activity Cognitive Performance CA1 CA2 CA3CA4 CP1 CP2 CP3 CP4 1 1 time1time2time3time4 time1time2time3time4 Bivariate Dual Change Score (Full Dynamics) Model 57.1* 60.9* -5.25* n.s 216.5* 246.6* n.s n.s age 0.03 n.s -5.9* *-0.05 n.s #slope and intercept factor inter-correlations are standardized estimates

Summary The decline in cognitive activities & global cognition is correlated over time but the change trajectories do not appear to influence each other. Cognitive activities are neither leading nor lagging indicators for cognitive decline over time. Relationship is likely due to a third variable that is unmeasured in our model

Next Steps We are currently writing up the manuscript for submission to JINS We are working on individual cognitive domains as the outcomes of the bivariate dual change score models.