Structural correlates of early and late onset Alzheimer's disease: voxel based morphometric study

Abstract

Objective: To examine the brain structural correlates of age at onset in patients with Alzheimer's disease. Methods: We studied nine patients with early onset (age (65 years), nine with late onset (age .65) Alzheimer's disease (EOAD and LOAD, respectively) of mild-moderate severity, and 26 controls who were stratified into younger (YC, age (65, n = 9) and older (OC, age .65, n = 17) subjects. The patients were closely matched for clinical severity: 3/2/3/1 patients had clinical dementia rating of 0.5/1/2/3, respectively, in both the groups. High resolution magnetic resonance images of the brain of the EOAD and YC groups and the LOAD and OC groups were compared on a voxel by voxel basis with statistical parametric mapping to detect areas specifically atrophic. Results: The patients with EOAD showed greater neocortical atrophy at the temporoparietal junction while the patients with LOAD showed greater hippocampal atrophy. The results could not be accounted for by the apolipoprotein E genotype. Conclusions: Since genetic factors are believed to play a relevant pathogenetic role in EOAD and environmental factors in LOAD, genetic and environmental factors may differentially predispose the neocortical and limbic areas to the development of Alzheimer's neuropathology.

Precuneus atrophy in early-onset Alzheimer’s disease: a morphometric structural MRI study

“…For the sake of completeness, we also performed a dichotomous analysis of our data with the cut-off at 65 years of age, which confirmed both the findings of the correlational analysis and the results of the previous VBM studies [3,4]. The severity of dementia, as measured by the MMSE, was higher in the younger patients although they appeared to have more preserved hippocampi.…”

“…For the sake of completeness and to facilitate comparison with earlier studies, we additionally performed a dichotomous analysis of EAD and LAD patients at an arbitrary cut-off of 65 years of age as used in earlier studies [3,4], using a two-sample t-test. Dichotomizing our group produced 35 patients with LAD and 20 patients with EAD (two LAD and two EAD patients were eventually excluded due to image pipeline failure as described above) with average ages of 74.7 years (SD 4.2, range 66-82 years) and 59.5 years (SD 4.3, 51-65 years) and MMSE scores of 21.5 (5.4, 4-28) and 16.2 (5.6, 8-24), respectively.…”

“…However, we did find clear differences in visuospatial functioning and processing speed and attention. Previous studies have also shown that the precuneus might have a smaller volume [3,4] or be functionally impaired [5,6] in younger patients with AD. Additionally, precuneus volume has been found to be a good classifier in a group of patients with AD [30].…”

“…So far, most MRI studies in AD have focused on elderly patients. Various MRI studies have suggested more posterior atrophy in patients with EAD [3,4]. Comparable areas in the brain have been identified with PET/SPECT studies [5][6][7].…”

The Prevalence of Alzheimer’s Disease and Dementia in Alzheimer’s Disease in Patients of Long-Term Nursing Home Care in the Podlaskie Province in Poland

“…Younger people and those who reached the age of 65 had largest grey matter atrophy, whereas patients over 65 had the remarkably atrophic hippocampus [15]. Similar conclusions were reported by authors from Italy and Finland [16].…”