Study Of Cognitive Aging Research Articles

Global Impact of Aging on the Hemodynamic Response Function in the Gray Matter of Human Cerebral Cortex.

In functional magnetic resonance imaging, the hemodynamic response function (HRF) is a stereotypical response to local changes in cerebral hemodynamics and oxygen metabolism due to briefly (< 4 s) evoked neural activity. Accordingly, the HRF is often used as an impulse response with the assumption of linearity in data analysis. In cognitive aging studies, it has been very common to interpret differences in brain activation as age-related changes in neural activity. Contrary to this assumption, however, evidence has accrued that normal aging may also significantly affect the vasculature, thereby affecting cerebral hemodynamics and metabolism, confounding interpretation of fMRI cognitive aging studies. In this study, use was made of a multisensory task to evoke the HRF in ~87% of cerebral cortex in cognitively intact adults with ages ranging from 22 to 75 years. This widespread activation enabled us to investigate age trends in the spatial distributions of HRF characteristics within the majority of cortical gray matter, which we termed as global age trends. The task evoked both positive and negative HRFs, which were characterized using model-free parameters in native-space coordinates. We found significant global age trends in the distributions of HRF parameters in terms of both amplitudes (e.g., peak amplitude and contrast-to-noise ratio) and temporal dynamics (e.g., full-width-at-half-maximum). Our findings offer insight into how age-dependent changes affect neurovascular coupling and show promise for use of HRF parameters as non-invasive indicators for age-related pathology.

Evaluating Social Determinants of Health-Based Alternatives to Race-Based Cognitive Normative Models.

Race and ethnicity are proxy measures of sociocultural factors that influence cognitive test performance. Our objective was to compare different regression-based cognitive normative models adjusting for demographics and different combinations of easily accessible/commonly used social determinants of health (SDoH) factors, which may help describe cognitive performance variability historically captured by ethnoracial differences. We performed cross-sectional analyses on data from Black and White participants without mild cognitive impairment/dementia in the Atherosclerosis Risk in Communities Study who attended visit 5 in 2011-2013. Participants underwent a battery of 11 cognitive tests (3 domains: memory, executive function, language). We fit 6 separate normative models for each cognitive test, all including age and education, with different combinations of race, the Wide Range of Achievement Test (education quality proxy), and area deprivation index (neighborhood deprivation) associated with current residence. We compared model fits and calculated concordances/discordances between models using z-scores derived from each normative model and a z-score <-1.5 threshold for impairment. Participants (n = 2,392) had a mean age of 74.4 years, 60.4% were female, and 17.1% were of self-reported Black race. The "Full" model with race alongside demographic and SDoH measures consistently outperformed other nested submodels (likelihood ratios ≥ 100) for all domains/tests except Delayed Word Recall. Models with education quality alone ("WRAT") generally outperformed models with neighborhood deprivation ("ADI") or race ("Race") alone for memory and language tests while "Race" models performed better for executive function tests. Adding neighborhood deprivation to education quality ("WRAT + ADI") did not improve models vs using "WRAT" alone. Across all domains/tests, the concordance compared with the "Full" model was lower for "Education" and "ADI" models than for other nested models. Although numbers were small, there was greater discordance among Black (range = 8.2%-23.2%) compared with White (range = 2.2%-3.4%) participants, particularly for Boston Naming Test and executive function tests. Education quality outperformed neighborhood disadvantage as an additional/alternative SDoH measure in normative models and may be useful to collect in cognitive aging studies. While performance varied across cognitive domains and tests, routinely reported SDoH variables (education level, education quality, late-life neighborhood deprivation) did not fully account for observed ethnoracial variability; future work should evaluate SDoH across the lifespan in more ethnoracially diverse populations.

The Role of Individual and Environmental Socio-Economic Resources for Cognitive Change in Very Old Age

ObjectivesVery old adults aged 80+ years old belong to the fastest growing population segment in many countries. Nevertheless, this age group is often underrepresented in studies of cognitive aging. The goal of this study was to examine individual and environmental socio-economic resources as correlates of cognitive aging in very old age. MethodWe used two waves of data from 2017-2018 and 2019-2021 as part of NRW80+, a survey of a population-based sample of very old individuals who are registered with their main residence in North-Rhine Westphalia, the most populous federal state in Germany. The analyses are based on data from 797 participants, who provided data on at least one cognitive test at both waves. Individual socio-economic resources included education, income, wealth, and occupational prestige. Environmental factors were assessed at the municipality level, including population density, unemployment, (public) transportation, broadband availability, healthcare, and libraries. Control variables included age, sex, marital/partner status, living alone, and living in a nursing care institution. Data were analyzed with latent difference score models. ResultsEducation and wealth were independently associated with better cognitive function at baseline. None of the individual socio-economic variables was significantly related to change in cognitive function. Beyond these individual characteristics and control variables, higher population density and higher broadband availability, but also higher unemployment rate were associated with better baseline cognitive function. Greater distance to highways, but also fewer hospital beds and a higher number of residents per medical doctor were associated with less decline. DiscussionOur findings suggest that individual socio-economic resources continue to be associated with better cognitive function in very old age, but are unrelated to short-term cognitive decline. In addition, there is some evidence for associations of baseline cognitive function and cognitive change with environmental factors over and above individual resources. Implications for future research are discussed.

Characterizing the progression from mild cognitive impairment to dementia: a network analysis of longitudinal clinical visits

BackgroundWith the recent surge in the utilization of electronic health records for cognitive decline, the research community has turned its attention to conducting fine-grained analyses of dementia onset using advanced techniques. Previous works have mostly focused on machine learning-based prediction of dementia, lacking the analysis of dementia progression and its associations with risk factors over time. The black box nature of machine learning models has also raised concerns regarding their uncertainty and safety in decision making, particularly in sensitive domains like healthcare.ObjectiveWe aimed to characterize the progression of health conditions, such as chronic diseases and neuropsychiatric symptoms, of the participants in Mayo Clinic Study of Aging (MCSA) from initial mild cognitive impairment (MCI) diagnosis to dementia onset through network analysis.MethodsWe used the data from the MCSA, a prospective population-based cohort study of cognitive aging, and examined the changing association among variables (i.e., participants’ health conditions) from the first visit of MCI diagnosis to the visit of dementia onset using network analysis. The number of participants for this study are 97 with the number of visits ranging from 2 visits (30 months) to 7 visits (105 months). We identified the network communities among variables from three-fold collection of instances: (i) the first MCI diagnosis, (ii) progression to dementia, and (iii) dementia diagnosis. We determine the variables that play a significant role in the dementia onset, aiming to identify and prioritize specific variables that prominently contribute towards developing dementia. In addition, we explore the sex-specific impact of variables in relation to dementia, aiming to investigate potential differences in the influence of certain variables on dementia onset between males and females.ResultsWe found correlation among certain variables, such as neuropsychiatric symptoms and chronic conditions, throughout the progression from MCI to dementia. Our findings, based on patterns and changing variables within specific communities, reveal notable insights about the time-lapse before dementia sets in, and the significance of progression of correlated variables contributing towards dementia onset. We also observed more changes due to certain variables, such as cognitive and functional scores, in the network communities for the people who progressed to dementia compared to those who does not. Most changes for sex-specific analysis are observed in clinical dementia rating and functional activities questionnaire during MCI onset are followed by chronic diseases, and then by NPI-Q scores.ConclusionsNetwork analysis has shown promising potential to capture significant longitudinal changes in health conditions, spanning from the MCI diagnosis to dementia progression. It can serve as a valuable analytic approach for monitoring the health status of individuals in cognitive impairment assessment. Furthermore, our findings indicate a notable sex difference in the impact of specific health conditions on the progression of dementia.

Genome-wide association study of subfoveal choroidal thickness in a longitudinal cohort of older adults

To identify genetic influences on subfoveal choroidal thickness of older adults using a genome-wide association study (GWAS). We recruited 300 participants from the population-based Korean Longitudinal Study on Health and Aging (KLoSHA) and Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD) cohort studies and 500 participants from the Bundang age-related macular degeneration (AMD) cohort study dataset. We conducted a GWAS on older adult populations in the KLoSHA and KLOSCAD cohorts. Single nucleotide polymorphisms (SNPs) associated with choroidal thickness were identified with P values < 1.0 × 10−4 in both the right and left eyes, followed by validation using the Bundang AMD cohort dataset. This association was further confirmed by a functional in vitro study using human umbilical vein endothelial cells (HUVECs). The ages of the cohort participants in the discovery and validation datasets were 73.5 ± 3.3 and 71.3 ± 7.9 years, respectively. In the discovery dataset, three SNPs (rs1916762, rs7587019, and rs13320098) were significantly associated with choroidal thickness in both eyes. This association was confirmed for rs1916762 (genotypes GG, GA, and AA) and rs7587019 (genotypes GG, GA, and AA), but not for rs13320098. The mean choroidal thickness decreased by 56.7 μm (AA, 73.8%) and 31.1 μm (GA, 85.6%) compared with that of the GG genotype of rs1916762, and by 55.4 μm (AA, 74.2%) and 28.2 μm (GA, 86.7%) compared with that of the GG genotype of rs7587019. The SNPs rs1916762 and rs7587019 were located close to the FAM124B gene near its cis-regulatory region. Moreover, FAM124B was highly expressed in vascular endothelial cells. In vitro HUVEC experiments showed that the inhibition of FAM124B was associated with decreased vascular endothelial proliferation, suggesting a potential mechanism of choroidal thinning. FAM124B was identified as a susceptibility gene affecting subfoveal choroidal thickness in older adults. This gene may be involved in mechanisms underlying retinal diseases associated with altered choroidal thickness, such as age-related macular degeneration.

LONGITUDINAL CHANGE OF RETINAL LAYER THICKNESS IN COGNITIVELY NORMAL ELDERLY SUBJECTS: Population-Based Cohort Study.

To identify longitudinal retinal layer thickness changes in normal eyes of cognitively healthy elderly people. Post hoc analysis was performed on 57 cognitively healthy elderly participants from the population-based Korean Longitudinal Study on Health and Aging and Korean Longitudinal Study on Cognitive Aging and Dementia cohort studies who underwent baseline and final optical coherence tomography scans. The peripapillary retinal nerve fiber layer, subfoveal choroid, and average retinal layer thickness at four quadrant (nasal, temporal, superior, and inferior) points 1 mm, 2 mm, and 3 mm from the center of the fovea were measured. The mean age of subjects was 75.1 years and the mean follow-up period was 55.9 months. Among the analyzed retinal layers, both the ganglion cell-inner plexiform layer and the outer nuclear layer at all 1 mm, 2 mm, and 3 mm points showed a statistically significant decrease in thickness at the final visit compared with baseline. The annual decrease rates were -1.2 µm/year at 1 mm (total -6.6%), -1.3 µm/year at 2 mm (total -8.4%), and -1.1 µm/year at 3 mm (total -9.7%) for ganglion cell-inner plexiform layer and -0.6 µm/year at 1 mm (total -4.2%), -0.5 µm/year at 2 mm (total -3.9%), and -0.4 µm/year at 3 mm (total -4.1%) for outer nuclear layer. Aging plays a significant role in the reduction of ganglion cell-inner plexiform layer and outer nuclear layer thicknesses in cognitively healthy elderly individuals.

Life course financial mobility and later-life memory function and decline by gender, and race and ethnicity: an intersectional analysis of the US KHANDLE and STAR cohort studies

Intersectionality has rarely been considered in research studies of cognitive ageing. We investigated whether life-course financial mobility is differentially associated with later-life memory function and decline across intersectional identities defined by gender, and race and ethnicity. Data were from two harmonised multiethnic cohorts (the Kaiser Healthy Aging and Diverse Life Experiences cohort and the Study of Healthy Aging in African Americans cohort) in northern California, USA (n=2340). Life-course financial mobility, measured using a combination of self-reported financial capital measures in childhood (from birth to age 16years) and later adulthood (at the cohort baseline) was defined as consistently high, upwardly mobile, downwardly mobile, or consistently low. We clustered individuals into 32strata representing intersectional identities defined by life-course financial mobility combined with gender, and race and ethnicity. Verbal episodic memory was assessed using the Spanish and English Neuropsychological Assessment Scales over four waves from 2017to 2023. Adjusted mixed-effects linear regression models were estimated with and without fixed effects of gender, race and ethnicity, and financial mobility, to evaluate whether the random effects of the intersectional identity strata contributed variance to memory beyond individual fixed effects. Mean age was 73·6years (SD 8·1). Of 2340individuals, 1460 (62·4%) were women, 880 (37·6%) were men, 388 (16·6%) were Asian, 1136 (48·5%) were Black, 334 (14·3%) were Latinx, and 482 (20·6%) were White. Consistently low and downwardly mobile financial capital were strongly negatively associated with later-life memory at baseline (-0·162SD units [95% CI -0·273to -0·051] for consistently low and -0·171 [-0·250to -0·092] for downwardly mobile), but not rate of change over time. Intersectional identities contributed 0·2% of memory variance after accounting for the fixed effects of gender, race and ethnicity, and financial mobility. Consistently low and downward life-course financial mobility are associated with lower later-life memory function. Intersectional identities defined by financial mobility in addition to gender, and race and ethnicity, contribute negligible additional variance to later-life memory in this study setting. US National Institute on Aging, US National Institutes of Health.

The Common Marmoset as a Translational Model for Longitudinal Studies of Cognitive Aging and Individual Vulnerability to Decline.

In humans, cognitive aging is highly variable, with some individuals experiencing decline while others remain stable, and different cognitive domains exhibiting uneven vulnerability to aging. The neural mechanisms driving this intra- and inter-individual variability are not fully understood, making longitudinal studies in translational models essential for elucidating the timelines and processes involved. The common marmoset (Callithrix jacchus), a short-lived nonhuman primate, offers an unprecedented opportunity to conduct longitudinal investigations of aging and age-related disease over a condensed time frame, in a highly translatable animal model. The potential of the marmoset as a model for cognitive aging is indisputable, but a comprehensive cognitive battery tailored for longitudinal aging studies has not yet been developed, applied, or validated. This represents a critical missing piece for evaluating the marmoset as a model and understanding the extent to which marmoset cognitive aging mirrors the patterns found in humans, including whether marmosets have individual variability in their vulnerability to age-related cognitive decline. To address this, we developed a comprehensive touchscreen-based neuropsychological test battery for marmosets (MarmoCog), targeting five cognitive domains: working memory, stimulus-reward association learning, cognitive flexibility, motor speed, and motivation. We tested a large cohort of marmosets, ranging from young adults to geriatrics, over several years. We found significant variability in cognitive aging, with the greatest decline occurring in domains dependent on the prefrontal cortex and hippocampus. Additionally, we observed significant inter-individual variability in vulnerability to age-related cognitive decline: some marmosets declined across multiple domains, others in just one, and some showed no decline at all. This pattern mirrors human cognitive aging, solidifies the marmoset as an advantageous model for age-related cognitive decline, and provides a strong foundation for identifying the neural mechanisms involved.

A genetically informed study of digital screen time, video game play, and impulsivity in established adulthood

High levels of digital screen time are associated with heightened impulsivity, though the assumption that this relationship is causal has seldom been rigorously examined. Moreover, the nature of this association may vary across life stages. Adults in established adulthood (ages 30–45) often face increased career and family commitments, which may impact leisure activities and the relationship between screen time and impulsivity. This study examined the association between digital screen time, video game play, and facets of impulsivity (i.e., perseverance, premeditation, and urgency) in adults in established adulthood using a multi-method approach, including a genetically-informed co-twin design. By comparing within-twin pair differences in screen time and impulsivity, the co-twin approach controls for genetic and environmental confounding, providing a quasi-experimental design. The sample included 1289 participants (Mage = 33.46, %Female = 52.75%, Ntwins = 704) from the Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging (CATSLife). After controlling for adolescent impulsivity, phenotypic analysis found that digital screen time was positively associated with higher levels of urgency and lack of perseverance. Co-twin control analysis showed that the association between digital screen time and urgency persisted within twin pairs, suggesting that shared familial and genetic factors may not fully explain the relationship. Video game play did not show consistent associations with impulsivity. These findings suggest that the immediacy and rapid succession of stimuli in digital screen engagement could be associated with impulsive tendencies in established adulthood, independent of video game play. The study underscores the need for nuanced examination to understand the interplay between digital engagement and impulsivity in this unique life stage.

The memory binding test in a longitudinal study of cognitive aging and preclinical disease.

The Memory Binding Test (MBT) shows promise in detecting early cognitive changes associated with Alzheimer's disease (AD). This study assesses the psychometric properties (i.e., construct and criterion validity, test-retest reliability) of the MBT and its sensitivity to incipient disease and incident cognitive impairment. One hundred forty-nine cognitively unimpaired adults ages 45-85 completed the MBT and neuropsychological tests at baseline; 132 returned for 2-year follow-up. Based on neuroradiological ratings of amyloid positron emission tomography and MRI markers at baseline, they were categorized as healthy (n = 94) or having preclinical disease (n = 55, either on the AD continuum or having non-AD pathologic change). Construct validity was assessed by the associations between MBT scores, demographics, and neuropsychological scores within the healthy group. Criterion validity was assessed by testing how MBT scores correlate with AD biomarkers, differ and discriminate between groups at baseline, and predict incident cognitive impairment. MBT scores decreased with age and were strongly associated with memory and global cognition. MBT scores were largely not associated with amyloid, hippocampal volume, or AD signature cortical volume but related to white matter lesion volume in those with preclinical disease. The preclinical groups performed worse on MBT immediate free recall at baseline than the healthy group, but no scores predicted incident cognitive impairment at follow-up. Most scores demonstrated modest test-retest reliability. This study demonstrates that the MBT has adequate construct validity in cognitively unimpaired adults, moderate sensitivity to preclinical disease cross-sectionally, and limited prognostic utility. Careful consideration of demographic influences on score interpretation remains necessary. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Individual differences in sociocognitive traits in semi-free-ranging rhesus monkeys (Macaca mulatta).

Characterizing individual differences in cognition is crucial for understanding the evolution of cognition as well as to test the biological consequences of different cognitive traits. Here, we harnessed the strengths of a uniquely large, naturally-living primate population at the Cayo Santiago Biological Field Station to characterized individual differences in rhesus monkey performance across two social cognitive tasks. A total of n = 204 semi-free-ranging adult rhesus monkeys participated in a data collection procedure, where we aimed to test individuals on both tasks at two time-points that were one year apart. In the socioemotional responses task, we assessed monkeys' attention to conspecific photographs with neutral versus negative emotional expressions. We found that monkeys showed overall declines in interest in conspecific photographs with age, but relative increases in attention to threat stimuli specifically, and further that these responses exhibited long-term stability across repeated testing. In the gaze following task we assessed monkeys' propensity to co-orient with an experimenter. Here, we found no evidence for age-related change in responses, and responses showed only limited repeatability over time. Finally, we found some evidence for common individual variation for performance across the tasks: monkeys that showed greater interest in conspecific photographs were more likely to follow a human's gaze. These results show how studies of comparative cognitive development and aging can provide insights into the evolution of cognition, and identify core primate social cognitive traits that may be related across and within individuals.

Lifestyle and psychosocial associations with cognition at the cusp of midlife using twins and siblings.

This study investigates the relationship between cognitive functioning and 59 modifiable and intrinsic factors at the cusp of midlife. We analyzed data from 1221 participants in the Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging (CATSLife; Mage=33.20, %Female=52.74). We assessed the impact of 59 factors on cognitive functioning using regularized regression and co-twin control models, controlling for earlier-life cognitive functioning and gray matter volume. Eight robust factors were identified, including education attainment, cognitive complexity, purpose-in-life, and smoking status. Twins reporting higher levels of cognitive complexity and purpose-in-life showed better cognitive performance than their cotwin, while smoking was negatively associated. Using meta-analytically derived effect size threshold, we additionally identified that twins experiencing more financial difficulty tend to perform less well compared with their cotwin. The findings highlight the early midlife link between cognitive functioning and lifestyle/psychological factors, beyond prior cognitive performance, brain status, genetic and familial confounders. Our results further highlight the potential of established adulthood as a crucial window for dementia prevention interventions targeting lifestyle and psychosocial factors. Cog complexity(+), purpose-in-life(+) were associated with cognition in early midlife.Smoking(-) was also associated with cognition in early midlife.Results were consistent controlling for genetic and environmental confounds.Association between EA and cognition might be mostly genetic and familial confounded.

Supplemental Material for The Memory Binding Test in a Longitudinal Study of Cognitive Aging and Preclinical Disease

Supplemental Material for The Memory Binding Test in a Longitudinal Study of Cognitive Aging and Preclinical Disease

Source-Specific Air Pollution and Loss of Independence in Older Adults Across the US

Air pollution is a recognized risk factor associated with chronic diseases, including respiratory and cardiovascular conditions, which can lead to physical and cognitive impairments in later life. Although these losses of function, individually or in combination, reduce individuals' likelihood of living independently, little is known about the association of air pollution with this critical outcome. To investigate associations between air pollution and loss of independence in later life. This cohort study was conducted as part of the Environmental Predictors Of Cognitive Health and Aging study and used 1998 to 2016 data from the Health and Retirement Study. Participants included respondents from this nationally representative, population-based cohort who were older than 50 years and had not previously reported a loss of independence. Analyses were performed from August 31 to October 15, 2023. Mean 10-year pollutant concentrations (particulate matter less than 2.5 μm in diameter [PM2.5] or ranging from 2.5 μm to 10 μm in diameter [PM10-2.5], nitrogen dioxide [NO2], and ozone [O3]) were estimated at respondent addresses using spatiotemporal models along with PM2.5 levels from 9 emission sources. Loss of independence was defined as newly receiving care for at least 1 activity of daily living or instrumental activity of daily living due to health and memory problems or moving to a nursing home. Associations were estimated with generalized estimating equation regression adjusting for potential confounders. Among 25 314 respondents older than 50 years (mean [SD] baseline age, 61.1 [9.4] years; 11 208 male [44.3%]), 9985 individuals (39.4%) experienced lost independence during a mean (SD) follow-up of 10.2 (5.5) years. Higher exposure levels of mean concentration were associated with increased risks of lost independence for total PM2.5 levels (risk ratio [RR] per 1-IQR of 10-year mean, 1.05; 95% CI, 1.01-1.10), PM2.5 levels from road traffic (RR per 1-IQR of 10-year mean, 1.09; 95% CI, 1.03-1.16) and nonroad traffic (RR per 1-IQR of 10-year mean, 1.13; 95% CI, 1.03-1.24), and NO2 levels (RR per 1-IQR of 10-year mean, 1.05; 95% CI, 1.01-1.08). Compared with other sources, traffic-generated pollutants were most consistently and robustly associated with loss of independence; only road traffic-related PM2.5 levels remained associated with increased risk after adjustment for PM2.5 from other sources (RR per 1-IQR increase in 10-year mean concentration, 1.10; 95% CI, 1.00-1.21). Other pollutant-outcome associations were null, except for O3 levels, which were associated with lower risks of lost independence (RR per 1-IQR increase in 10-year mean concentration, 0.94; 95% CI, 0.92-0.97). This study found that long-term exposure to air pollution was associated with the need for help for lost independence in later life, with especially large and consistent increases in risk for pollution generated by traffic-related sources. These findings suggest that controlling air pollution could be associated with diversion or delay of the need for care and prolonged ability to live independently.

Ideational Slippage in Middle-Aged and Older Adults: A Preliminary Study.

Ideational slippage-characterized by incorrect word usage and strained logic during dialogue-is common in aging and, at greater frequency, is an indicator of pre-clinical cognitive decline. Performance-based assessment of ideational slippage may be useful in the study of cognitive aging and Alzheimer's-disease-related pathology. In this preliminary study, we examine the association between corpus callosum volume and a performance-based assessment of ideational slippage in middle-aged and older adults (age 61-79 years). Ideational slippage was indexed from cognitive special scores using the Rorschach Inkblot Method (RIM), which are validated indices of deviant verbalization and logical inaccuracy (Sum6, WSum6). Among middle-aged and older adults, smaller splenium volume was associated with greater ideational slippage (ηp2 = 0.48), independent of processing speed and fluid intelligence. The observed negative associations are consistent with visuospatial perception and cognitive functions of the splenium. The effect was strongest with the splenium, and volumes of the genu and total white matter had small effects that were not statistically significant. Conclusions: Results are discussed with future application of RIM special scores for the assessment of pre-clinical cognitive decline and, based on observed effect sizes, power analyses are reported to inform future study planning.

Eligibility for the Donanemab Trial in a Population-Based Study of Cognitive Aging (N4.001)

Eligibility for the Donanemab Trial in a Population-Based Study of Cognitive Aging (N4.001)

Mild Behavioral Impairment in a Population-based Study of Cognitive Aging (P2-9.005)

Mild Behavioral Impairment in a Population-based Study of Cognitive Aging (P2-9.005)

A twin-driven analysis on early aging biomarkers and associations with sitting-time and physical activity.

Current physical activity guidelines may be insufficient to address health consequences in a world increasing in sedentary behavior. Physical activity is a key lifestyle factor to promote healthy aging, but few studies examine activity in conjunction with sitting. We examine how activity intensity and sitting behavior influence health and the extent to which physical activity might counter sitting. We analyzed data from the Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging (CATSLife) in adults aged 28-49 years (M = 33.16, SD = 4.93). We fit a linear mixed-effect model for body mass index (BMI) and total cholesterol/high-density lipoprotein ratio (TC/HDL). Leveraging the co-twin control approach, we explore the trade-off between sitting and physical activity. Across established adulthood, TC/HDL and BMI demonstrated increasing age trends with prolonged sitting and vigorous activity inversely associated. Moreover, after considering sitting time, we found an age-equivalent benefit of vigorous exercise where those performing 30 minutes daily had expected TC/HDL and BMI estimates that mirrored sedentary individuals 5 and 10 years younger, respectively. Co-twin control analysis suggests partial exposure effects for TC/HDL, indicating greater vigorous activity may counter sitting-health effects but with diminishing returns. Our findings support the counteracting influence of prolonged sitting and physical activity on indicators of cardiovascular and metabolic health. A compensating role of vigorous activity on sitting health links is indicated while reducing sitting time appears paramount. Public health initiatives should consider sitting and vigorous activity in tandem in guidelines to promote health maintenance and combat accelerated aging.

Predicting Brain Amyloid Status Using the National Institute of Health Toolbox (NIHTB) for Assessment of Neurological and Behavioral Function.

Amyloid-beta (Aβ) plaque is a neuropathological hallmark of Alzheimer's disease (AD). As anti-amyloid monoclonal antibodies enter the market, predicting brain amyloid status is critical to determine treatment eligibility. To predict brain amyloid status utilizing machine learning approaches in the Advancing Reliable Measurement in Alzheimer's Disease and Cognitive Aging (ARMADA) study. ARMADA is a multisite study that implemented the National Institute of Health Toolbox for Assessment of Neurological and Behavioral Function (NIHTB) in older adults with different cognitive ability levels (normal, mild cognitive impairment, early-stage dementia of the AD type). Participants across various sites were involved in the ARMADA study for validating the NIHTB. 199 ARMADA participants had either PET or CSF information (mean age 76.3 ± 7.7, 51.3% women, 42.3% some or complete college education, 50.3% graduate education, 88.9% White, 33.2% with positive AD biomarkers). We used cognition, emotion, motor, sensation scores from NIHTB, and demographics to predict amyloid status measured by PET or CSF. We applied LASSO and random forest models and used the area under the receiver operating curve (AUROC) to evaluate the ability to identify amyloid positivity. The random forest model reached AUROC of 0.74 with higher specificity than sensitivity (AUROC 95% CI:0.73 - 0.76, Sensitivity 0.50, Specificity 0.88) on the held-out test set; higher than the LASSO model (0.68 (95% CI:0.68 - 0.69)). The 10 features with the highest importance from the random forest model are: picture sequence memory, cognition total composite, cognition fluid composite, list sorting working memory, words-in-noise test (hearing), pattern comparison processing speed, odor identification, 2-minutes-walk endurance, 4-meter walk gait speed, and picture vocabulary. Overall, our model revealed the validity of measurements in cognition, motor, and sensation domains, in associating with AD biomarkers. Our results support the utilization of the NIH toolbox as an efficient and standardizable AD biomarker measurement that is better at identifying amyloid negative (i.e., high specificity) than positive cases (i.e., low sensitivity).

AGING AND NUMERACY: A META-ANALYSIS

Abstract Numeracy, the ability to competently make use of numbers and numerical information, is a unique cognitive ability associated with diverse positive outcomes across the lifespan. Often included as a covariate in studies of cognitive aging, there is some scattered evidence of lower numeracy in older adults when compared to younger adults. Importantly, one longitudinal study found evidence of a quadratic decline in numeracy starting in later middle-age. The current study systematically reviews the literature on aging and numeracy as measured by one of three frequently implemented objective measures: the Lipkus numeracy scale (Lipkus et al., 2001), Weller et al.’s Rasch-based numeracy scale (2013), and the Berlin Numeracy Test (Cokely et al., 2012). Effect sizes were calculated from two types of studies: those including age as a categorical extreme group comparison variable or as a continuous variable from adult lifespan samples. Hedge’s g was computed as the effect size in the former studies and Pearson’s r was calculated as the effect size for the latter. For comparison across studies in a single random-effects model, Pearson’s r effect sizes were mathematically transformed into Hedge’s g’s. Type of sample (extreme group vs. adult lifespan) and age range were included in a second mixed-effects model to account for heterogeneity in effect sizes. Initial results show lower numeracy in older adults, but reduced effect size estimates in lifespan samples compared to those using extreme group comparisons. The implications for using linear estimates of effect size for the quadratic relationship between age and numeracy are discussed.