Correlates of SuperAging in Two Population-Based Samples of Hispanic Older Adults

OBJECTIVES

'SuperAgers' are generally defined as people 80+ years old with episodic memory performance comparable to those 20 years younger. Limited knowledge exists to describe characteristics of SuperAgers, with even less known about Hispanic SuperAgers.

METHODS

We examined indicators of cognitive, physical, and psychological resilience in relation to the likelihood of being a SuperAger using data from two population-based studies of Hispanic older adults [Puerto Rican Elder: Health Conditions (PREHCO) study; Health and Retirement Study (HRS)]. SuperAgers were defined as 1) ≥80 years old, 2) recall scores ≥ the median for Hispanic respondents aged 55-64, and 3) no cognitive impairment during the observation period. Overall, 640 PREHCO participants and 180 HRS participants were eligible, of whom 45 (7%) and 31 (17%) met SuperAging criteria.

RESULTS

Logistic regressions controlling for age and sex demonstrated that higher education (PREHCO: odds ratio[OR]=1.20, p<.001; HRS: OR=1.14, p=.044) and fewer instrumental activities of daily living (IADL) limitations (PREHCO: OR=0.79, p=.019; HRS: OR=0.58, p=.077) (cognitive resilience), fewer activities of daily living (ADL) limitations (PREHCO: OR=0.72, p=.031; HRS: OR=0.67, p=.068) (physical resilience), and fewer depressive symptoms (PREHCO: OR=0.84, p=.015; HRS: OR=0.69, p=.007) (psychological resilience) were associated with SuperAging, although not all results reached threshold for statistical significance, presumably due to low statistical power. Additionally, known indicators of physical health (e.g., chronic conditions, self-rated health) did not relate to SuperAging.

DISCUSSION

Increasing access to education and recognizing/treating depressive symptoms represent potential pathways to preserve episodic memory among older Hispanic adults.

Amyloid-β PET Classification on Cognitive Aging Stages Using the Centiloid Scale

PROPOSE

This study aims to explore the use of the Centiloid (CL) method in amyloid-β PET quantification to evaluate distinct cognitive aging stages, investigating subjects' mismatch classification using different cut-points for amyloid-β positivity.

PROCEDURES

The CL equation was applied in four groups of individuals: SuperAgers (SA), healthy age-matched controls (AC), healthy middle-aged controls (MC), and Alzheimer's disease (AD). The amyloid-β burden was calculated and compared between groups and quantitative variables. Three different cut-points (Jack CR, Wiste HJ, Weigand SD, et al., Alzheimer's Dement 13:205-216, 2017; Salvadó G, Molinuevo JL, Brugulat-Serrat A, et al., Alzheimer's Res Ther 11:27, 2019; and Amadoru S, Doré V, McLean CA, et al., Alzheimer's Res Ther 12:22, 2020) were applied in CL values to differentiate the earliest abnormal pathophysiological accumulation of Aβ and the established Aβ pathology.

RESULTS

The AD group exhibited a significantly increased Aβ burden compared to the MC, but not AC groups. Both healthy control (MC and AC) groups were not significantly different. Visually, the SA group showed a diverse distribution of CL values compared with MC; however, the difference was not significant. The CL values have a moderate and significant relationship between Aβ visual read, RAVLT DR and MMSE. Depending on the cut-point used, 10 CL, 19 CL, or 30 CL, 7.5% of our individuals had a different classification in the Aβ positivity. For the AC group, we obtained about 40 to 60% of the individuals classified as positive.

CONCLUSION

SuperAgers exhibited a similar Aβ load to AC and MC, differing in cognitive performance. Independently of cut-point used (10 CL, 19 CL, or 30 CL), three SA individuals were classified as Aβ positive, showing the duality between the individual's clinics and the biological definition of Alzheimer's. Different cut-points lead to Aβ positivity classification mismatch in individuals, and an extra care is needed for individuals who have a CL value between 10 and 30 CL.

Paucity of Entorhinal Cortex Pathology of the Alzheimer's Type in SuperAgers with Superior Memory Performance

Advancing age is typically associated with declining memory capacity and increased risk of Alzheimer's disease (AD). Markers of AD such as amyloid plaques (AP) and neurofibrillary tangles (NFTs) are commonly found in the brains of cognitively average elderly but in more limited distribution than in those at the mild cognitive impairment and dementia stages of AD. Cognitive SuperAgers are individuals over age 80 who show superior memory capacity, at a level consistent with individuals 20-30 years their junior. Using a stereological approach, the current study quantitated the presence of AD markers in the memory-associated entorhinal cortex (ERC) of seven SuperAgers compared with six age-matched cognitively average normal control individuals. Amyloid plaques and NFTs were visualized using Thioflavin-S histofluorescence, 6E10, and PHF-1 immunohistochemistry. Unbiased stereological analysis revealed significantly more NFTs in ERC in cognitively average normal controls compared with SuperAgers (P < 0.05) by a difference of ~3-fold. There were no significant differences in plaque density. To highlight relative magnitude, cases with typical amnestic dementia of AD showed nearly 100 times more entorhinal NFTs than SuperAgers. The results suggest that resistance to age-related neurofibrillary degeneration in the ERC may be one factor contributing to preserved memory in SuperAgers.

The "SuperAgers" construct in clinical practice: neuropsychological assessment of illiterate and educated elderly

INTRODUCTION

The demographic transition is a global event intensified during the last decades that represents population aging. Thus, the studies directed to the elderly 80 years of age or more with preserved cognitive functions (named SuperAgers) emerges as a possible path to full comprehension of the health of those aging with acceptable levels of functionality and independency.

OBJECTIVE

To evaluate the cognitive performance of the elderly over 80 years old, associating the results to their educational level.

METHOD

We evaluated 144 healthy elders with 80 years or more through the following cognitive tests Mini-Mental State Examination (MMSE), Cambridge Cognitive Examination (CAMCOG), Clock Drawing Test (CDT), and Verbal Fluency Test (VF) and compared the tests' scores with their educational level segmented in years of formal education, being the groups ILLITR (<1 year of schooling), 1TO4 (from 1 to 4 years of schooling), and 5MORE (>5 years of schooling).

RESULTS

There was positive influence of educational level on the cognitive tests' score, which indicates higher cognitive reserve of the elderly with higher educational levels.

CONCLUSION

The functionality and independence of the so-called SuperAgers is determined by the cognitive reserve acquired throughout life, mainly developed by the years of formal education.

Stability of memory SuperAgers over 3 years

Some people aged 80 years and older are "memory SuperAgers" (SAs), that is, they have the episodic memory of a sexagenarian. In a sample of 208 non-demented adults, we found that 12% were SAs. A total of 101 participants completed the 4-year study; of this subsample, 10.9% were stable SAs and 61.3% stable non-SAs across all assessments. The SA phenotype is conducive to further research.