C-07 Global Precedence: Examining Contributing Effects of Age and Cognitive Functioning

Abstract

Objective Global precedence (GP) is an individual’s ability to readily identify global (gestalt) features when both global and local (internal) details are presented. Prior research shows that both age and neurodegenerative diseases, such as Alzheimer’s, affect GP. The goal of the current study is to examine differences in GP between individuals with early-onset Alzheimer’s disease (EOAD; before age 65) and healthy controls (HC). Method Fourteen EOAD patients and 6 HC’s recruited from Behavioral Neurology at an academic medical center were included in the current analysis. EOAD participants were diagnosed by clinical history, routine labs, neuroimaging, and neurological examination. Exclusion criteria included unstable medical conditions and history of severe head injury, psychotic disorder, or psychoactive substance use. All participants completed a Mini Mental Status Examination (MMSE) to assess overall cognitive functioning and a 4-item Navon's paradigm task (consisting of a larger letter whose shape is composed of smaller repeats of a different letter) to assess for GP. Results Linear regression analysis was performed, with the total score on Navon task as the dependent variable and age, MMSE score, and study group as predictor variables. Analysis yielded significant findings, suggesting a difference in GP performance between the two groups. However, coefficients suggested that while age did not contribute to the between-group difference, MMSE scores significantly accounted for our findings. In fact, when effects of MMSE scores were controlled, the between-group difference was no longer significant. Conclusion Findings suggest that individuals with EOAD perform worse on tasks of GP, which may be secondary to overall cognitive decline.