Deviations in Hippocampal Subregion in Older Adults With Cognitive Frailty

Abstract

BackgroundCognitive frailty is a particular state of cognitive vulnerability toward dementia with neuropathological hallmarks. The hippocampus is a complex, heterogeneous structure closely relates to the cognitive impairment in elderly which is composed of 12 subregions. Atrophy of these subregions has been implicated in a variety of neurodegenerative diseases. The aim of this study was to explore the changes in hippocampal subregions in older adults with cognitive frailty and the relationship between subregions and cognitive impairment as well as physical frailty.MethodsTwenty-six older adults with cognitive frailty and 26 matched healthy controls were included in this study. Cognitive function was evaluated by the Montreal Cognitive Assessment (MoCA) scale (Fuzhou version) and Wechsler Memory Scale-Revised Chinese version (WMS-RC), while physical frailty was tested with the Chinese version of the Edmonton Frailty Scale (EFS) and grip strength. The volume of the hippocampal subregions was measured with structural brain magnetic resonance imaging. Partial correlation analysis was carried out between the volumes of hippocampal subregions and MoCA scores, Wechsler’s Memory Quotient and physical frailty indexes.ResultsA significant volume decrease was found in six hippocampal subregions, including the bilateral presubiculum, the left parasubiculum, molecular layer of the hippocampus proper (molecular layer of the HP), and hippocampal amygdala transition area (HATA), and the right cornu ammonis subfield 1 (CA1) area, in older adults with cognitive frailty, while the proportion of brain parenchyma and total number of white matter fibers were lower than those in the healthy controls. Positive correlations were found between Wechsler’s Memory Quotient and the size of the left molecular layer of the HP and HATA and the right presubiculum. The sizes of the left presubiculum, molecular of the layer HP, and HATA and right CA1 and presubiculum were found to be positively correlated with MoCA score. The sizes of the left parasubiculum, molecular layer of the HP and HATA were found to be negatively correlated with the physical frailty index.ConclusionSignificant volume decrease occurs in hippocampal subregions of older adults with cognitive frailty, and these changes are correlated with cognitive impairment and physical frailty. Therefore, the atrophy of hippocampal subregions could participate in the pathological progression of cognitive frailty.

Cognitive abilities of institutionalized older persons with depressive symptoms

“…Such subregions are associated with functions such as cognitive processing (information input and output capacity), visuospatial function, memory, fear regulation (situational learning and emotional memory) and hippocampal circuitry function and cognitive behavior. Thus, this more severe atrophy in the brain parenchyma and a reduction in the total number of white matter fibers in the group of older adults with cognitive frailty may indicate the pathway of association between low short-term memory, depressive symptoms and lower physical abilities 59 .…”

Brain structural alterations and clinical features of cognitive frailty in Japanese community-dwelling older adults: the Arao study (JPSC-AD)

“…Although previous studies have indicated that white matter hyperintensity lesions are associated with CF, this is the first report of a population-based study. In addition, we analyzed SVD in more detail than in previous studies 13 – 15 , including evaluations of lacunar infarcts and microbleeds. We also examined MTL region volumes because volume reductions have been linked to early pathological changes in Alzheimer’s disease, the most frequent dementia to develop from amnestic MCI.…”

“…Four recent studies have investigated brain structural changes associated with CF using magnetic resonance imaging (MRI) 12 – 15 . These studies reported that compared to healthy adults without CF, those with CF had increased white matter hyperintensity lesions 12 , 13 and greater volume reductions (atrophy) in the bilateral thalamus, left caudate, right pallidum, right accumbens 14 , and bilateral hippocampal subregions 15 . These lesion and atrophy patterns suggest that CF is a sign of progressive vascular pathology and neurodegenerative processes.…”

“…Previous brain imaging studies have defined CF according to original definitions 13 – 15 or as “reversible cognitive deficits” 12 rather than by a stricter operational definition that can reliably differentiate CF from PF, MCI, and normal aging groups. Therefore, we conducted a CF study using data from a population-based cross-sectional survey that defined CF according to the “potentially reversible CF IANA/IAGG model of cognitive frailty.” Also, rather than using an arbitrary screening value for MCI (clinical dementia rating = 0.5), MCI was determined by a physician trained to distinguish between MCI and other diseases like dementia and depression as described by Solffrizzi et al 18 .…”

Hypertension Status Moderated the Relationship between the Hippocampal Subregion of the Left GC-ML-DG and Cognitive Performance in Subjective Cognitive Decline

“…In the progression of AD, specific anatomical areas of the hippocampus tend to atrophy [ 17 ]. In older adults with cognitive frailty, a significant volume decrease occurs in the bilateral presubiculum, the left parasubiculum, the hippocampal amygdala transition area (HATA), and the CA1 area [ 18 ], while compared to the MCI, the volume of the right molecular layer/right CA4 is significantly smaller and correlated with the cognitive performance (measured with MMSE) in AD [ 19 , 20 ]. Although the above research showed difference alteration in the hippocampal subregions in the progression of AD, a comprehensive study on the structural characteristics of the hippocampal subregion networks which are affected by hypertension in SCD is lacking.…”