Lifestyle and brain health determinants of word-finding failures in healthy ageing

Abstract

AbstractCognitive decline associated with healthy ageing is complex and multifactorial: vascular and lifestyle factors uniquely and jointly contribute to distinct neurocognitive trajectories of ageing. To evaluate existing accounts of neurocognitive ageing that propose mechanisms of compensation, maintenance or reserve, studies should explore how various known brain-based and lifestyle factors intersect to better understand cognitive decline. Here, we bring together brain function, structure, perfusion, and cardiorespiratory fitness to investigate a well-documented, prominent cognitive challenge for older adults: word-finding failures. Commonality analysis on 73 neurologically healthy older adults revealed that functional activation of language networks associated with tip-of-the-tongue states is in part determined by age and, interestingly, cardiorespiratory fitness levels. Age-associated atrophy and perfusion in regions other than those showing functional differences accounted for variance in tip-of-the-tongue states. Our findings can be interpreted in the context of the classic models of neurocognitive ageing, with mechanisms of compensation and reserve interacting with each other.HighlightsThe incidence of word-finding failures is determined by brain health and lifestyle factorsLanguage network activation associated with word-finding failures is determined by age and cardiorespiratory fitness levelsDistinct contribution of brain structure and perfusion also predict this declineBrain health indices in concordance with lifestyle measures provide a holistic explanation of individual differences in age-related cognitive decline