A – 100 Comparing Cortical and Hippocampal Atrophy Effects on Executive Functioning

Abstract Objective This study investigates how increasing levels of atrophy severity (none to severe) in the Cerebral Cortex and Hippocampus influence executive functioning, as measured by Trails B performance. The differential impact of atrophy severity was compared between these two brain regions to explore their respective roles in dementia-related decline in executive functioning. Method Trails B performance data was analyzed from the National Alzheimer's Coordinating Center (NACC) from 16,800 participants (Mage = 79.56) with varying degrees of atrophy due to Alzheimer’s disease and other forms of dementia. Atrophy level was determined by neuroimaging (MRI and PET) using standard criteria based on the NACC public database. Data processing and analysis were performed using Julius AI. Results Severity levels (none and severe) within Hippocampal and Cerebral Cortex atrophies were compared, followed by a comparison between regions. After controlling for age and education, the ANCOVA analyses comparing the mean difference between severe to no atrophy in the Hippocampal and Cerebral Cortex regions approached significance, F(4, 16791) = 3.35, p = .067, 95% CI: [-1.47, 44.09]. Cerebral Cortex atrophy demonstrated greater decline across severity (mean difference = 105.97s) compared to Hippocampal atrophy (mean difference = 84.66s). Conclusion Increased atrophy severity in Cerebral Cortex and Hippocampal regions were associated with decreased performance on Trails B, with Cerebral Cortex showing slightly greater effects. Although significance was not reached, findings suggest underlying correlates to deficits in information processing and memory, warranting further investigation into differentiating the critical role of Cortical and Hippocampal integrity in neurodegenerative-related changes in executive functioning.