Neural correlates of perceived physical and mental fatigability in older adults: A pilot study

This pilot work examined associations of brain grey matter volumes (GMV) with perceived fatigability in older adults to elucidate disablement mechanisms. A subsample (n = 29; age = 77.2 ± 5.5; 86% female) of participants from the Lifestyle Interventions and Independence for Elders (LIFE) Study was utilized to quantify GMV for regions of interest in the basal ganglia and limbic system normalized to intracranial volume. The Pittsburgh Fatigability Scale measured physical and mental fatigability (score 0-50; higher physical fatigability ≥ 15; higher mental fatigability ≥ 13). We used an exploratory alpha level of p < 0.1. Nineteen (66%) participants had higher physical fatigability, 19 (66%) had higher mental fatigability, of these, 17 (57%) had both. Right hippocampal volumes/ICV were smaller in participants with higher verses lower physical fatigability (0.261 ± 0.039 vs. 0.273 ± 0.022, p = 0.07); associations were similar for right putamen and bilateral thalamus. Higher mental fatigability was associated with smaller right hippocampus, thalamus, and posterior cingulum and bilateral amygdala. Higher fatigability in older adults may be associated with smaller volumes of the basal ganglia and limbic system, indicating mechanisms for further exploration.