Hippocampal volume and integrity as predictors of cognitive decline in intact elderly

Abstract

Risk of Alzheimer’s disease (AD) can be predicted by volumetric analyses of MRI data in the medial temporal lobe. The present study compared a volumetric measurement of the hippocampus to a novel measure of hippocampal integrity derived from the ratio of parenchyma volume over total volume. Participants were cognitively intact and aged 60 or older at baseline, and were tested twice, roughly three years apart. Participants had been recruited for a study on late-life major depression (LLMD) and were evenly split between depressed and controls. Linear regression models were applied to the data with a cognitive composite score as outcome, and hippocampal integrity (HI) and volume (HV), together or separately, as predictors. Subsequent cognitive performance was predicted well by models that include an interaction between HI and LLMD-status, such that lower HI scores predicted more cognitive decline in depressed subjects. More research is needed, but tentative results from this study appear to suggest that the newly introduced measure HI is an effective tool for the purpose of predicting future changes in general cognitive ability, and especially so in individuals with LLMD.

Association between composite scores of domain-specific cognitive functions and regional patterns of atrophy and functional connectivity in the Alzheimer’s disease spectrum

“…Our findings agree with the majority of previous studies that assessed the associations of regional gray matter volume with either single test measures of cognitive function, or composite measures of cognitive domains derived by averaging across standardized scores of single tests of cognitive function in both healthy elderly cohorts ( Chee et al, 2009 , Bruno et al, 2016 , Cacciaglia et al, 2018 ) and patients ( Di Paola et al, 2007 , Mitolo et al, 2013 , Ranasinghe et al, 2014 , Smits et al, 2014 , Cacciaglia et al, 2018 ). These previous and our findings differ from a previous MEG and MRI study Ranasinghe et al (2014) that found no correlation between gray matter atrophy and cognitive performance, however, the number of cases n = 27 in this previous study was very low.…”

“…Further notable networks in which decreased rsFC has been associated with deficits in the respective cognitive domains in monocentric cohorts include the EN ( Agosta et al, 2012 , Ranasinghe et al, 2014 ) and DMN ( Greicius et al, 2004 , Dong et al, 2012 ). Additionally, a number of studies have also probed the possible associations between regional structural atrophy and cognitive deficits in both healthy elderly cohorts ( Chee et al, 2009 , Bruno et al, 2016 , Cacciaglia et al, 2018 ) and AD-spectrum patients ( Di Paola et al, 2007 , Mitolo et al, 2013 , Ranasinghe et al, 2014 , Smits et al, 2014 , Cacciaglia et al, 2018 ), using varying measures of cognition. Associations of course, do not only depend on the imaging methods employed but also on the way cognitive performance is being quantified.…”

Age and hippocampal volume predict distinct parts of default mode network activity

“…Evidence of volumetric decrement of this structure is considered an important marker of AD-related neuronal injury 24 . Moreover, this variable is also informative among healthy adults, as hippocampal volume and integrity are predictors of cognitive decline in this population 25 . Finally, this variable offers a major methodological advantage over other potential proxies of AD (e.g., the score on the Mini Mental State Examination), because it is characterised by an ample numerical variability among old as well as young adults 26 , and, specifically in this latter sub-population, it is associated with memory performance 27,28 .…”

Sexual Dimorphism and Hemispheric Asymmetry of Hippocampal Volumetric Integrity in Normal Aging and Alzheimer Disease

“…23 The HPF has also been found to be a better predictor of future cognitive decline than volume. 25 In this article, we measured the bilateral HPF on 3D volumetric MR imaging scans acquired from older adult subjects with and without AD-type dementia obtained through a publicly available data base. We then used linear mixed-effects statistical models to study the relationship between the magnitude and bilateral asymmetry of the HPF with respect to subject age, sex, and dementia severity.…”