Abstract
IntroductionThe hippocampus plays an important role in cognitive abilities which often decline with advancing age.MethodsIn a longitudinal study of community‐dwelling adults, we investigated whether there were coupled changes in hippocampal structure and verbal memory, working memory, and processing speed between the ages of 73 (N = 655) and 76 years (N = 469). Hippocampal structure was indexed by hippocampal volume, hippocampal volume as a percentage of intracranial volume (H_ICV), fractional anisotropy (FA), mean diffusivity (MD), and longitudinal relaxation time (T1).ResultsMean levels of hippocampal volume, H_ICV, FA, T1, and all three cognitive abilities domains decreased, whereas MD increased, from age 73 to 76. At baseline, higher hippocampal volume was associated with better working memory and verbal memory, but none of these correlations survived correction for multiple comparisons. Higher FA, lower MD, and lower T1 at baseline were associated with better cognitive abilities in all three domains; only the correlation between baseline hippocampal MD and T1, and change in the three cognitive domains, survived correction for multiple comparisons. Individuals with higher hippocampal MD at age 73 experienced a greater decline in all three cognitive abilities between ages 73 and 76. However, no significant associations with changes in cognitive abilities were found with hippocampal volume, FA, and T1 measures at baseline. Similarly, no significant associations were found between cognitive abilities at age 73 and changes in the hippocampal MRI biomarkers between ages 73 and 76.ConclusionOur results provide evidence to better understand how the hippocampus ages in healthy adults in relation to the cognitive domains in which it is involved, suggesting that better hippocampal MD at age 73 predicts less relative decline in three important cognitive domains across the next 3 years. It can potentially assist in diagnosing early stages of aging‐related neuropathologies, because in some cases, accelerated decline could predict pathologies.
Highlights
The hippocampus plays an important role in cognitive abilities which often decline with advancing age
Our results provide evidence to better understand how the hippocampus ages in healthy adults in relation to the cognitive domains in which it is involved, suggesting that better hippocampal mean diffusivity (MD) at age 73 predicts less relative decline in three important cognitive domains across the 3 years
We assessed the relationship between cognitive changes and changes in general hippocampal volume, hippocampal volume as a percentage of intracranial volume (H_ICV), fractional anisotropy (FA), MD, and T1 over a 3-year period
Summary
The hippocampus plays an important role in cognitive functions such as memory, learning, and spatial navigation (Förster et al, 2012; Muzzio, Kentros, & Kandel, 2009; Nossin-Manor et al, 2012). Some studies have shown substantial overlap between hippocampal volume in healthy controls and patients with Alzheimer’s disease once adjusted for intracranial capacity, and the range of hippocampal volumes is large in healthy adults (Barnes et al, 2004; Antonio Convit et al, 1993; Lupien et al, 2007; L. van de Pol, Hensel, van der Flier et al, 2006). This suggests that volume alone does not fully indicate hippocampal integrity, and smaller adjusted volumes may not necessarily signify deterioration. We assessed the relationship between cognitive changes and changes in general hippocampal volume, hippocampal volume as a percentage of intracranial volume (H_ICV), FA, MD, and T1 over a 3-year period
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
