Subiculum volumes associated with memory function in the oldest‐old individuals aged 95 years and older

Abstract

Aim Few cohort studies targeting the oldest‐old individuals have been carried out. The subiculum in the hippocampus is thought to be related to memory function, and atrophy of this structure might result in the conversion from amnestic mild cognitive impairment to Alzheimer's disease. Thus, we sought to examine the relationship between subiculum volumes and memory function in individuals aged ≥95 years, using a novel cognitive examination called the Addenbrooke's Cognitive Examination III (ACE‐III) and an advanced magnetic resonance imaging analytical method, Multiple Automatically Generated Templates Brain Segmentation Algorithm (MAGeTbrain), to measure hippocampal subfield volumes. Methods A part of the cohort data of the Arakawa 95+ study for the oldest‐old aged ≥95 years was used. A total of 10 individuals completed all of the examinations. The MAGeT brain was applied to estimate the subfield volumes of the hippocampus. Correlation analyses and multiple regression analyses were carried out to examine a relationship among ACE‐III memory scores and the subfield volumes in the hippocampus, including the subiculum. Results There was a significant relationship between ACE‐III memory scores and subdivision volumes. Regression analyses showed that subiculum volumes were associated with ACE‐III memory scores in the oldest‐old individuals (β = 0.721, P = 0.019; F1, 8 = 8.67, adjusted R2 = 0.46). Conclusions The subiculum might play a pivotal role in memory function in the oldest‐old individuals aged ≥95 years. The present finding warrants further research including larger sample sizes. Geriatr Gerontol Int 2019; 19: 347–351.

Neuroimaging in the Oldest-Old: A Review of the Literature

“…A combination of low hippocampal and high WMH volume was associated with the fastest decline on all cognitive tests [35]. Another recent study in the oldest-old found associations between volumes of hippocampal subfields and memory scores in a cohort of participants aged 95 or older (N = 10, mean age 97.6 years) [36].…”

“…• Lower hippocampal volumes were associated with a faster rate of decline in global cognition along with lower test scores in the following domains: global cognition, memory, processing speed, and executive functioning [35]. Smaller subiculum volumes were associated with lower memory scores on the ACE-III [36].…”

Bridging Patterns of Neurocognitive Aging Across the Older Adult Lifespan

“…Slower rates of memory decline have also been associated with larger baseline whole brain volume across the older adult lifespan (Carmichael et al, 2012). Cross-sectional studies similarly report that oldest-old adults with larger hippocampus volumes have better episodic memory performance (Eguchi et al, 2019) and faster processing speeds (Legdeur et al, 2020;Pelkmans et al, 2021), comparable to what has been reported in younger-old adults (Carr et al, 2017;Gorbach et al, 2017;O'Shea et al, 2016).…”

Bridging patterns of neurocognitive aging across the older adult lifespan

“…Slower rates of memory decline have also been associated with larger baseline whole brain volume across the older adult lifespan (Carmichael et al, 2012). Cross-sectional studies similarly report that oldest-old adults with larger hippocampus volumes have better episodic memory performance (Eguchi et al, 2019) and faster processing speeds (Legdeur et al, 2020;Pelkmans et al, 2021), comparable to what has been reported in younger-old adults (Carr et al, 2017;Gorbach et al, 2017;O'Shea et al, 2016). Larger volume of the hippocampus was also found to predict better memory performance in individuals across the lifespan (ages 4-93 years; Langnes et al, 2020).…”