Clinical observations have suggested that the neuropsychological profile of early and late onset forms of Alzheimer's disease (EOAD and LOAD) differ in that neocortical functions are more affected in the former and learning in the latter, suggesting that they might be different diseases. The aim of this study is to assess the brain structural basis of these observations, and test whether neocortical areas are more heavily affected in EOAD and medial temporal areas in LOAD. Fifteen patients with EOAD and 15 with LOAD (onset before and after age 65; Mini Mental State Examination 19.8, SD 4.0 and 20.7, SD 4.2) were assessed with a neuropsychological battery and high-resolution MRI together with 1:1 age- and sex-matched controls. Cortical atrophy was assessed with cortical pattern matching, and hippocampal atrophy with region-of-interest-based analysis. EOAD patients performed more poorly than LOAD on visuospatial, frontal-executive and learning tests. EOAD patients had the largest atrophy in the occipital [25% grey matter (GM) loss in the left and 24% in the right hemisphere] and parietal lobes (23% loss on both sides), while LOAD patients were remarkably atrophic in the hippocampus (21 and 22% loss). Hippocampal GM loss of EOAD (9 and 16% to the left and right) and occipital (12 and 14%) and parietal (13 and 12%) loss of LOAD patients were less marked. In EOAD, GM loss of 25% or more was mapped to large neocortical areas and affected all lobes, with relative sparing of primary sensory, motor, and visual cortex, and anterior cingulate and orbital cortex. In LOAD, GM loss was diffusely milder (below 15%); losses of 15-20% were confined to temporoparietal and retrosplenial cortex, and reached 25% in restricted areas of the medial temporal lobe and right superior temporal gyrus. These findings indicate that EOAD and LOAD differ in their typical topographic patterns of brain atrophy, suggesting different predisposing or aetiological factors.

The likelihood of rupture of unruptured intracranial aneurysms that were less than 10 mm in diameter was exceedingly low among patients in group 1 and was substantially higher among those in group 2. The risk of morbidity and mortality related to surgery greatly exceeded the 7.5-year risk of rupture among patients in group 1 with unruptured intracranial aneurysms smaller than 10 mm in diameter.

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ET might slow down age-related gray matter loss in postmenopausal women. The structures that exhibited greater volume in association with ET included the cerebellar and cerebral cortices and, typically involved in Alzheimer's disease, the medial temporal structures and the temporoparietal junction.

Purpose:To compare the accuracy of voxel-based morphometry (VBM) and region of interest (ROI)-based hippocampal volumetry to detect medial temporal lobe atrophy in Alzheimer's disease (AD). Materials and Methods:A total of 27 AD patients (age 74 Ϯ 9 years; 22 women; Mini-Mental State Exam [MMSE] 21 Ϯ 4) and 25 controls (age 70 Ϯ 8; 16 women; MMSE 29 Ϯ 1) were studied. Accuracy of VBM to detect gray matter loss in those seven AD patients and 11 controls with similar ROIbased hippocampal measures and of ROI-based volumetry to detect gray matter loss in those four AD patients and five controls with similar VBM-based hippocampal measures was assessed. VBM was performed with statistical parametric mapping (SPM99). Results:The area under the curve was 0.96 (95% C.I., 0.92-1.00) for VBM, 0.89 (95% C.I., 0.80 -0.98) for ROIbased hippocampal measures, and 0.99 (95% C.I., 0.96 -1.00) for both. In subjects with similar ROI-based hippocampal measures, VBM detected atrophy in AD patients at P Ͻ 0.0001, while in subjects with similar VBM-based hippocampal measure, volumetry was not significant (P ϭ 0.11). Both measures independently contributed to discrimination (P ϭ 0.004 and P ϭ 0.032) in a logistic regression model. Conclusion:These results indicate that VBM is more accurate, but the combination of both methods provides the highest accuracy for detection of hippocampal atrophy in AD.