| Publication Abstract Display | | Type: Poster | | Title: Cognitive and physiologic reserve uniquely relate to superior neurocognitive abilities in adults aging with HIV. | | Authors: Saloner R, Lobo JD, Paolillo E, Letendre SL, Cherner M, Grant I, Heaton RK, Moore DJ | | Date: 02-03-2021 | | Abstract:Objective: Research on older people with HIV (PWH) is predominated by deficit models that focus on the combined neurobiological burdens of HIV and aging, yet many older PWH exhibit intact neurocognition. We have recently identified a subset of older PWH with "youthful" and resilient neurocognitive abilities characteristic of SuperAging (SA). Cognitive reserve (CR) and physiologic reserve (PR), which reflect the capacity to withstand neural and systemic stressors, respectively, are putative neuroprotective factors that have not been jointly studied in the context of SA among older PWH. The present study examined the independent contributions of CR and PR to global and domain-specific patterns of superior neurocognitive abilities in older PWH.
Participants and Methods: 475 PWH (age range: 50-69 years) underwent neuropsychological and neuromedical evaluations. Three neurocognitive status groups were defined as follows. SA was defined as demographically-corrected (i.e., sex, race/ethnicity, education) global cognitive performance within the normal range for 25-year-olds. Non-SA participants were subsequently classified as cognitively normal (CN) or impaired (CI) based on actual age-corrected norms. The same normative thresholds were applied for secondary analyses in which neurocognitive status was re-classified based on single-domain performance. CR was operationalized using actual age-corrected standard scores on the Wide-Range Achievement Test-IV Reading subtest. PR was operationalized using a cumulative index of medical disease burden comprising 39 general (e.g., hypertension, triglycerides) and HIV-specific health deficits (e.g., HIV plasma viral load). Health deficits were reverse coded as present (0) or absent (1) such that higher scores indicated a lower proportion of health deficits (i.e., higher PR). Statistical methods included analysis of variance with confirmatory multinomial logistic regression to determine global and domain-specific group differences in CR and PR.
Results: Groups were 74 (16%) SA, 206 (43%) CN, and 195 (41%) CI. Univariably, SA exhibited significantly higher CR and PR compared to CN (CR: d=0.46, p<.001; PR: d=0.39, p=.004) and CI (CR: d=0.35, p=.01; PR: d=0.32, p=.02), whereas CN and CI did not significantly differ on CR (d=0.11, p=.27) or PR (d=-.07, p=.48). Covarying for age, higher CR and PR uniquely predicted higher odds of classification as SA (odds ratios>1.42 per 1 SD increase, ps<0.05). Domain-specific analyses indicated significantly higher 1) PR in participants who met SA criteria for information processing speed, psychomotor speed, and delayed recall, and 2) higher CR in those who met SA criteria for executive functioning, working memory and delayed recall (ps<.05).
Conclusions: SuperAgers had higher CR and PR, even compared to cognitively normal (but not Super) older PWH, suggesting high premorbid intelligence and physiological functioning independently buffer against adverse neurocognitive effects in older PWH. Reserve factors related to discrete SA domain profiles and may reflect nonoverlapping pathways of neuroprotection. Specifically, PR may support cognitive efficiency through maintenance of psychomotor and processing speed, whereas CR may reflect optimal higher-order neurocognitive functions. Both reserve dimensions related to superior memory, a particularly aging-vulnerable neurocognitive domain. Determining how these factors jointly support optimal real-world outcomes in SA with HIV points towards development of specific interventions to improve or maintain quality of life in older PWH. |
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