Early-onset and late-onset Alzheimer's disease (EOAD and LOAD) are two forms of the disease with the same characteristic neuropathological hallmarks. However, higher burdens of neuritic plaques and neurofibrillary tangles in frontal and parietal lobes have been found in EOAD than in LOAD patients. Thus, the EOAD subjects may have a differentiated clinical presentation compared to the LOAD ones. Some authors have found less hippocampal memory presentations and more focal cortical abnormalities (such as visuoconstructive or executive dysfunction) in EOAD than LOAD patients. The aim of the present study was to determine which initial clinical profiles differ between EOAD and LOAD; and to analyze whether another age cut-off could discriminate better between EOAD and LOAD clinical presentations than the conventional limit of 65. All patients fulfilling NINCDS-ADRDA criteria for probable Alzheimer's disease who referred to our Hospital between October 2007 and December 2012 were included in the study. The conventional age limit of 65 was established to distinguish between EOAD and LOAD. Baseline neuropsychological scores, adjusted for age and education, were compared between both groups. A total of 181 patients (38 EOAD, 143 LOAD) entered in the analysis. Sex distribution and time of evolution of symptoms did not differ between groups. The EOAD patients performed worse than LOAD in attentional, imitation praxis and verbal learning tests. In addition, the age cut-off of 70 was found to differentiate between early- and late-onset groups better than the standard cut-off of 65 years old. Our results support a differentiated neuropsychological impairment pattern in EOAD compared to LOAD.

No abstract

Up to 60% of the patients with Alzheimer’s disease (AD) can have cortical or brainstem Lewy bodies (LB), and extrapyramidal signs (EPS) have been found to be associated with LB in AD patients. However, the relationship between EPS and brain volumes has not been studied in the LB variant of AD using structural magnetic resonance imaging (MRI). The purpose of this study was to determine the relationship between patterns of brain atrophy and clinical EPS in patients with pathologically confirmed AD. We compared gray matter structure using voxel-based morphometry in 29 Definite AD cases, 16 (55%) of whom also had LBs identified with α-synuclein immunohistochemistry. Multivariate models analyzed brain volume at a voxel level accounting for subject group, Mini-Mental State Examination (MMSE), EPS, total brain volume, and the time from MRI scan to death. There was no significant difference in gray matter volume in the Definite AD patients as a function of LB. There was a significant association between gray matter volumes and the MMSE in AD patients, both with and without LBs. There was a significant correlation between gray matter volume and EPS only in the group of AD patients with LBs, and not in those with pure AD. These findings suggest that that the etiology of EPS in patients with the LB variant of AD is associated with neuronal loss in the nigrostriatal tracts. By contrast, the source of the EPS in AD alone appears to be less well localized.