Volumetric MRI Measurements Can Differentiate Alzheimer's Disease, Mild Cognitive Impairment, and Normal Aging

Abstract

Background: Volumetric magnetic resonance imaging (MRI) has been extensively studied in the last decade as a method to help with the clinical diagnosis of Alzheimer's disease (AD). In recent years, researchers have also started investigating if that technique would be useful to identify individuals with mild cognitive impairment (MCI), differentiating them from AD patients and from normal elderly controls. This research project was planned to assess the accuracy of volumetric MRI to differentiate those groups of individuals. Method: The investigation involved 39 patients with diagnosis of mild to moderate dementia in AD, according to the criteria of the NINCDS-ADRDA, DSM-III-R, and ICD-10; 21 subjects with complaints of cognitive decline without other psychiatric disorders (MCI); and 20 normal elderly controls. All the subjects were submitted to a standard protocol, including volumetric MRI evaluations. Results: The results indicated that all regions of interest measured (amygdala, hippocampus, and parahippocampal gyrus) were significantly different (p < .005) in AD patients compared to MCI subjects and controls. The left volumetric measures (amygdala, hippocampus, and parahippocampal gyrus) were also significantly different between the MCI subjects and controls (p < .05). The discriminant function analysis correctly classified 88.14% of the AD patients and controls, 81.67% of AD patients and MCI subjects, and 80.49% of the MCI subjects and controls. Conclusions: The results suggest that measures of medial temporal lobe regions are useful to identify mild to moderate AD patients and MCI subjects, separating them from normal elderly individuals.

Multicentre variability of MRI-based medial temporal lobe volumetry in Alzheimer's disease

“…This finding agrees with previous studies reporting significant reductions of hippocampus volumes in AD compared to MCI patients [40] and with longitudinal studies [22] suggesting that hippocampus volume continues to shrink even in manifest stages of AD. One previous study reported reduced amygdala volumes in AD compared to MCI patients [5]. The effect size for amygdala volume reduction was -1.0 for left and -1.1 for right amygdala in this previous study which is within the expected range of effect size estimates as defined by the 95% confidence limits of the sampling distribution of the multicentre effect sizes from our study (figures 2 and 4).…”

Premature or pathological aging: longevity

“…In blood testing for E4 allele, 20 control patients (healthy older individuals), 41 patients with Alzheimer's and 21 with mild cognitive impairment (MCI) were analyzed. In this study, Bottino et al (2002) discovered rates that indicate that older people with E4 allele have 2.4 times more risk of developing Alzheimer's disease.…”

Parahippocampal corpora amylacea and neuronal lipofuscin in human aging

“…The presence of the two older groups (second and the third) in our study, in which age was not significantly different but the number of lipofuscin-bearing neurons and CA were, might be explained as the consequence of different brain aging patterns [49]. Finally, such a metabolic state of the parahippocampal gyrus neurons can indirectly support Keller's [4] hypothesis that such senescence-related changes, like CA and lipofuscin deposits, might represent predecessors for more serious changes, like the ones observed in the early phase of AD in the entorhinal area as part of the parahippocampal region [5][6][7][8][9][10][11][12][13][14][15]. Future research should include the development of in vivo methods of CA and lipofuscin deposit detection and quantification in the brain of the elderly individuals.…”

“…Taking into the consideration the importance of the MTL in memory processing, a large number of cross-sectional volumetric neuroimaging studies were performed. They predominantly focused on the comparison of MTL structure volumes, or the degree of their atrophy, between healthy individuals, age-matched cases suffering from mild cognitive impairment (MCI) and cases at different stages of Alzheimer's disease (AD) [5][6][7][8][9][10][11][12][13][14][15]. Their results showed a significant reduction of MTL component volumes in cases with mild cognitive impairment and AD.…”

“…These findings, and the fact that in the early phases of AD the first pathological changes occur in the entorhinal cortex [5][6][7][8][9][10][11][12][13][14][15], stressed the importance of the histological findings, especially of MTL areas, that might improve the understanding of the cellular basis for the various degrees of cognitive decline within healthy elderly populations. Until recently it was generally believed that age-related impairments in cognitive performance are the result of age-related neuron loss, especially within the hippocampus and most neocortical areas.…”