University of North Carolina at Chapel Hill Graduate School
Doi
Abstract
The U.S. population is aging at its greatest rate in history. An older average population will increase the number of age-related cognitive issues. Elucidation of factors that contribute to decline with age and methods to prevent or decrease the incidence of cognitive dysfunction in the aging population is vital to offset the impact of the age shift. Validation of tests to identify and predict decline is the first step, but must be paired with an increased understanding of the inter- and intra-individual differences that influence cognitive decline. One difference, gut microbiome diversity, changes within the person across their lifespan and varies among individuals. An individual’s gut microflora can significantly influence gut-brain communication, brain function, and behavior. The study was focused on identification and prediction of cognitive decline using CANTAB and visual ERP as well as exploring the relation between gut-microbiome diversity and cognitive performance. Participants underwent tests to evaluate cognitive decline over time: the MoCA, a CANTAB battery for behavioral cognitive assessment, and an electrophysiological evaluation via a passive oddball paradigm and an active detection task. The role of microbiome diversity in cognitive decline was investigated, ERP measures were validated against CANTAB measures, the predictive relation between MoCA and future cognitive outcomes were characterized, and the utility of ERP PCA factors and CANTAB outcomes to predict future ERP and CANTAB performance were shown. Three CANTAB measures (RTI, SWM, and RVP) were independently confirmed to significantly relate to selected ERP measures in both the active detection and the passive oddball tasks. Baseline MoCA score and change in MoCA score significantly predicted outcomes in the CANTAB battery and ERP tasks at follow-up. The study also included the design and implementation of novel methodology with two-step temporospatial PCA to successfully predict future performance on ERP with baseline performance on the same task, which, to this author’s knowledge, is the first known use of this method for this purpose. Finally, significant relations between gut-microbiome diversity and healthy cognitive function were revealed, where lower microbial diversity significantly relates to poorer cognitive performance on both behavioral (CANTAB) and electrophysiological (ERP) measures.Doctor of Philosoph
