Role of the Neuropathology of Alzheimer Disease in Dementia in the Oldest-Old

Neuropathologic features associated with Alzheimer disease diagnosis

“…Even though the prevalence of vascular pathologies increased with age, the odds of AD based on vascular pathologies did not because people with normal cognition also had an increase in the frequency of vascular pathologies with age, though this was not statistically significant. Furthermore, a trend for diminished association between clinical AD and neuritic plaques and Lewy bodies, which was observed in other studies, 6,7,13,26 was attenuated when coexisting neuropathologic features were considered. This suggests that the preliminary observation of a trend toward weaker association between clinical AD and Lewy bodies and neuritic plaques in older age groups in this and other studies may be partially due to differing levels of coexisting neuropathologic features that also contribute to cognitive impairment across age groups (such as neurofibrillary tangles and microvascular disease).…”

“…[5][6][7][8][9][10][11][12][13][14][15] Preliminary studies that compared the strength of association between dementia diagnosis or cognitive performance and AD neuropathology (neuritic plaques and neurofibrillary tangles) between the young old and the oldest old suggest that the association is weaker among the oldest old 6,13 ; however, these studies were limited by small to moderate size and considered…”

“…For that reason, the weaker relationship between neurofibrillary tangles and clinical cognitive diagnosis among the oldest old may be an artifact of disease severity, rather than age group. However, this is unlikely given that Haroutunian et al 6 found that the association between AD pathology and dementia severity was also diminished among the oldest old. Second, the frequency of neurofibrillary tangles among those with normal cognition was higher in the oldest old than in other age groups.…”

Engaging in Cognitive Activities, Aging, and Mild Cognitive Impairment: A Population-Based Study

“…For instance, animals with enriched environments are protected against cognitive impairment 28, 30 . Additionally in clinical settings it is also observed that clinical manifestations may not correlate with the neuropathological burden on postmortem examination 6, 31-33 , implying that the cognitive reserve may serve as a buffer against the Alzheimer’s disease neuropathological burden. Since MCI is considered to be a prodromal state to Alzheimer’s disease, one can invoke the cognitive reserve theory to explain the inverse association between cognitive activities and the odds of having MCI.…”

Cognition and Neuropathology in Aging: Multidimensional Perspectives from the Rush Religious Orders Study and Rush Memory and Aging Project

“…In community based studies of cognition with autopsy [5][6][7], it has been found that a third of people without dementia can have plaques and tangles that meet criteria for intermediate or even high likelihood of Alzheimer's Disease (AD), as well as infarctions and Lewy bodies [8]. As such, the correlation between neuropathological lesions and cognition is modest and accounts for about a quarter of the variance of cognition among older adults [9][10][11][12].…”