Working Memory Mediates the Association between Dorsolateral Prefrontal Cortex Plasticity and Global Cognition in Alzheimer's Dementia and Older Healthy Comparison Individuals

BackgroundDorsolateral prefrontal cortex (DLPFC) plasticity is associated with working memory (WM) in a combine sample of individuals with Alzheimer’s dementia (AD) and older healthy comparison (HC). We hypothesized that DLPFC plasticity is associated with Global Cognition (GC) and that this association is mediated by WM. MethodsThirty-two AD and 20 HC participants were assessed using Repeatable Battery for the Assessment of Neuropsychological Status for GC, N-back task for WM, and electroencephalography combined with Paired Associative Stimulation of DLPFC for DLPFC plasticity. ResultsDLPFC plasticity was associated with GC (B [SE] = 21.65 [9.08]; β = 0.30; P = .02) in the combined group of AD and HC participants. WM mediated the association between DLPFC plasticity and GC (B= 18.67[6.52], 99%CI [2.11, 38.94). Conclusion This study suggests that DLPFC plasticity impacts GC via its impact on WM and significant relationship between DLPFC plasticity and GC may be mediated by WM.M.Sc