Antecedents and consequences of unawareness of memory impairment in dementia.

OBJECTIVE: To assess the prevalence, antecedents, and consequences of unawareness of memory impairment in dementia. METHOD: Persons (n = 1,862) from a geographically defined community without dementia at enrollment subsequently underwent clinical classification (248 with dementia, 611 with mild cognitive impairment, 1,003 with no cognitive impairment), memory testing, and self-appraisal of memory. Memory performance was regressed on self-appraised memory, and the residuals served as an index of memory awareness. After clinical classification, participants completed brief cognitive testing at 3-year intervals for up to 15 years. RESULTS: When unawareness was defined as a score at or below thresholds ranging from the 15th to 25th percentiles, it was more common in dementia (67%-83%) and mild cognitive impairment (15%-33%) than in no cognitive impairment (2%-6%; all p < .001). A continuous measure of awareness (M = 0.00, SD = 0.61) was reduced by 0.37-unit in mild cognitive impairment (SE = 0.04, p < .001) and 1.04-unit in dementia (SE = 0.06), p < .001) compared with those without cognitive impairment, and these associations were weaker in Black persons than White persons (estimate for dementia by race = 0.37, SE = 0.12, p = .003; estimate for mild cognitive impairment by race = 0.30, SE = 0.08, p < .001). Higher premorbid neuroticism was associated with better memory awareness in dementia. Higher memory awareness was not related to mortality in mild cognitive impairment or dementia but had a marginal association with slower cognitive decline in mild cognitive impairment. CONCLUSIONS: Unawareness of memory impairment is a common manifestation of dementia, particularly in White persons, but is not strongly related to adverse disease outcomes. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Anosognosia in Dementia.

Progressive decline in memory (and other functions) is the defining feature of late-life dementia but affected individuals are often unaware of this impairment. This article reviews recent research on anosognosia in dementia, including methods of assessing anosognosia, its prevalence and developmental course in dementia, its occurrence in different forms of dementia, neuroimaging findings, and hypothesized component mechanisms. The results suggest that anosognosia is eventually exhibited by nearly all persons with dementia. Its occurrence is robustly associated with common dementia-related pathologies and damage to memory and self-referential brain networks and their interconnections.

Temporal course and pathologic basis of unawareness of memory loss in dementia.

OBJECTIVE: To characterize the natural history and neuropathologic basis of unawareness of memory loss in late-life dementia. METHODS: Analyses are based on 2,092 older persons from 3 longitudinal clinical-pathologic cohort studies who had no memory or cognitive impairment at baseline. Annual evaluations included clinical classification of dementia plus self-rating and performance testing of memory. At death, there was a uniform neuropathologic examination to quantify 7 dementia-related pathologies. RESULTS: In the full group, memory ratings were modestly correlated with memory performance (intercepts r = 0.26, p < 0.001; slopes r = 0.23, p < 001) and so we regressed each person's memory performance on their memory ratings, and the residuals provided longitudinal indicators of memory awareness. In a subset of 239 persons who developed dementia, episodic memory awareness was stable until a mean of 2.6 years before dementia onset (95% credible interval -2.7, -1.6); thereafter, memory awareness declined rapidly (mean annual change -0.32, 95% credible interval -0.37, -0.28). Older age at baseline was associated with later onset of memory unawareness. In a subset of 385 persons who died and underwent neuropathologic examination, transactive response DNA-binding protein 43 (TDP-43) pathology, tau tangles, and gross cerebral infarcts were related to decline in memory awareness. In the absence of these pathologies, no decline in memory awareness was evident. Results were similar in subgroups with and without dementia. CONCLUSIONS: Awareness of memory impairment typically begins to decline about 2-3 years before dementia onset and is associated with postmortem evidence of TDP-43 pathology, tangles, and gross cerebral infarcts.

Cognitive aging in older Black and White persons.

During a mean of 5.2 years of annual follow-up, older Black (n = 647) and White (n = 647) persons of equivalent age and education completed a battery of 17 cognitive tests from which composite measures of 5 abilities were derived. Baseline level of each ability was lower in the Black subgroup. Decline in episodic and working memory was not related to race. Decline in semantic memory, perceptual speed, and visuospatial ability was slower in Black persons than White persons, and in semantic memory and perceptual speed this effect was stronger in older than younger participants. Racial differences persisted after adjustment for retest effects. The results suggest subtle cognitive aging differences between Black persons and White persons.

Conscientiousness, dementia related pathology, and trajectories of cognitive aging.

The study aim was to determine the contribution of dementia related pathologies to the association of conscientiousness with late-life cognitive health. At enrollment in 2 longitudinal clinical-pathologic cohort studies, 309 older individuals without cognitive impairment completed a standard conscientiousness measure. Annually thereafter, they completed a battery of 17 cognitive tests. On death, they underwent a uniform neuropathologic examination from which measures of neurofibrillary tangles, Lewy bodies, chronic gross cerebral infarction, and hippocampal sclerosis were derived. The relation of conscientiousness and the neuropathologic markers to cognitive decline was assessed in mixed-effects change point models to accommodate nonlinear cognitive decline. During a mean of 10.7 years of follow-up, annual decline on a composite measure of global cognition (baseline M = 0.082, SD = 0.499) was gradual (estimated M = -0.036, 95% CI [-0.046, -0.025]) until a mean of 3.2 years before death (95% CI [-3.6, -2.8]) when it accelerated to a mean annual loss of 0.369 unit (95% CI [-0.426, -0.317]), a tenfold increase. Higher conscientiousness (baseline M = 33.6, SD = 5.1) was associated with slower terminal decline (estimate = 0.064, 95% CI [0.024, 0.103]) but not preterminal decline (estimate = 0.005, 95% CI [-0.003, 0.013]). After adjustment for neuropathologic burden, conscientiousness was still related to terminal decline (estimate = 0.057, 95% CI [0.019, 0.094]) and accounted for 4% of the variance in terminal slopes. In addition, the association of neocortical Lewy bodies with terminal cognitive decline was attenuated in those with higher conscientiousness. The results suggest that higher conscientiousness is protective of late-life cognitive health.