Change in Cognitive Performance From Midlife Into Old Age: Findings from the Midlife in the United States (MIDUS) Study

Increased listening effort and cochlear neural degeneration underlie behavioral deficits in speech perception in noise in normal hearing middle-aged adults

Middle-age is a critical period of rapid changes in brain function that presents an opportunity for early diagnostics and intervention for neurodegenerative conditions later in life. Hearing loss is one such early indicator linked to many comorbidities later in life. However, current clinical tests fail to capture hearing difficulties for ∼10% of middle-aged adults seeking help at hearing clinics. Cochlear neural degeneration (CND) could play a role in these hearing deficits, but our current understanding is limited by the lack of objective diagnostics and uncertainty regarding its perceptual consequences. Here, using a cross-species approach, we measured envelope following responses (EFRs) - neural ensemble responses to sound originating from the peripheral auditory pathway - in young and middle-aged adults with normal audiometric thresholds, and compared these responses to young and middle-aged Mongolian gerbils, where CND was histologically confirmed. We observed near identical changes in EFRs across species that were associated with CND. Perceptual effects measured as behavioral readouts showed deficits in the most challenging listening conditions and were associated with CND. Additionally, pupil-indexed listening effort increased even at moderate task difficulties where behavioral outcomes were matched. Our results reveal perceptual deficits in middle-aged adults driven by CND and increases in listening effort, which may result in increased listening fatigue and conversational disengagement.

The Relationship Between 10-Year Changes in Cognitive Control Beliefs and Cognitive Performance in Middle and Later Adulthood

OBJECTIVES

The present study used a cross-lagged panel design with longitudinal data to test if there is a reciprocal relationship between cognitive control beliefs and cognition (e.g., executive functioning and episodic memory) over 10-years, whether frequency of engaging in stimulating cognitive activities mediated this relationship, and if these relationships varied by age.

METHODS

Data were collected as part of the second (M2, 2004-05) and third (M3, 2013-14) waves of the Midlife in the United States Study (MIDUS). The analysis sample included 2,532 participants with all variables at M2 and M3. Participants' ages ranged from 33 to 83 (M=54.92, SD=11.13) at M2.

RESULTS

There was a reciprocal relationship between cognitive control beliefs and executive functioning. Higher executive functioning was related to greater maintenance of cognitive control beliefs for older, not younger, adults. Higher cognitive control beliefs were related to less decline in executive functioning. Though cognitive control beliefs predicted 10-year changes in episodic memory, the inverse relationship was not supported. Frequency of engaging in stimulating cognitive activities mediated the relationship between executive functioning and 10-year changes in cognitive control beliefs, but not cognitive control beliefs and 10-year changes in cognition.

CONCLUSIONS

Cognitive control beliefs are a promising mechanism to help protect against age-related declines in both executive functioning and episodic memory. Moreover, executive functioning also impacts cognitive control beliefs. Specifically, those with higher executive functioning engage more frequently in stimulating cognitive activities, which helps maintain higher cognitive control beliefs.

Does Perceived Generativity Mediate the Association Between Optimism and Cognitive Function Over Time? Findings from Midlife in the United States Study

Cognitive function is a vital component of healthy aging. However, whether a persistently high optimism benefits late-life cognitive function is debatable. The current study examined associations between high optimism status, perceived generativity, and cognitive functions across adulthood. Data were from waves 2 and 3 (2004-14) of the Midlife in the United States study. We used structural equation modeling to examine whether participants' (N = 2,205; Mage = 65 ± 11) persistent high optimism predicts better cognitive functions over time, compared to high optimism at only one time-point or not at all while controlling for covariates; we also examined whether individuals' perceived generativity mediates the above association. The findings revealed that persistent high optimism was significantly associated with better episodic memory and executive function. Further, perceived generativity positively mediated the association between persistent high optimism and episodic memory. Future research should examine mechanisms for potential aspects of high optimism and perceived generativity on late-life cognitive performances.

Depressive Symptoms Affect Cognitive Functioning from Middle to Late Adulthood: Ethnoracial Minorities Experience Greater Repercussions

Cognitive deficits, a diagnostic criterion for depressive disorders, may precede or follow the development of depressive symptoms and major depressive disorder. However, an individual can report an increase in depressive symptoms without any change in cognitive functioning. While ethnoracial minority group differences exist, little is known to date about how the relationship between depressive symptoms and cognitive function may differ by ethnoracial minority status. Utilizing data from the Midlife in the United States (MIDUS) study waves II (M2) and III (M3), this study examines the relationship between depressive symptoms and cognitive functioning concurrently and longitudinally in community-dwelling adults, as well as whether the results differed by ethnoracial minority status. Our participants included 910 adults (43.8% male, 80.8% White, 54.4 ± 11.5 years old at M2). Cross-sectionally, depressive symptoms, ethnoracial minority status, and their interaction had significant effects on cognitive function, consistent with previous investigations. Longitudinally, higher M2 depressive symptoms predicted poorer cognitive function at M3 over and above M2 cognitive functioning, but only within the ethnoracial minority sample. Our finding suggests that depressive symptoms predict cognitive functioning both concurrently and across time, and this relationship is moderated by ethnoracial identity, resulting in greater cognitive deficits among ethnoracial minority groups compared to their non-Hispanic White counterparts.

Detecting and Predicting Cognitive Decline in Individuals with Traumatic Brain Injury: A Longitudinal Telephone-Based Study

Traumatic brain injuries (TBIs) can lead to long-lasting cognitive impairments, and some survivors experience cognitive decline post-recovery. Early detection of decline is important for care planning, and understanding risk factors for decline can elucidate targets for prevention. While neuropsychological testing is the gold standard approach to characterizing cognitive function, there is a need for brief, scalable tools that are capable of detecting clinically significant changes in post-TBI cognition. This study examines whether a clinically significant change can be detected using the Brief Test of Adult Cognition by Telephone (BTACT) in a sample of individuals with chronic TBI and investigates whether potentially modifiable factors are associated with cognitive decline. Ninety participants aged 40 or older with complicated mild-to-severe TBI participated in two telephone-based study visits ∼1 year apart. Demographic, head trauma exposure, comorbid medical conditions, physical, and psychosocial functioning data were collected via self-report. The BTACT, a brief measure of global cognitive function, was used to assess cognitive performance across six domains. A reliable change index for quantifying clinically significant changes in BTACT performance was calculated. Results revealed cognitive decline in 10-27% of participants across various cognitive domains. More specifically, only depressive symptoms, including depressed affect and anhedonia, were significantly associated with cognitive decline after correcting for multiple comparisons using false discovery rate (FDR). Other factors such as the number of blows to the head, male gender, dyspnea, increased anxiety symptoms, seizures, illicit drug use, and fewer cardiovascular comorbidities should be considered hypothesis generating. Importantly, age was not a significant predictor of cognitive decline, which challenges the assumption that cognitive decline is solely related to the natural aging process. It suggests that there are unique factors associated with TBI that impact cognitive function, and these factors can affect individuals across the lifespan. The BTACT is a brief and sensitive tool for identifying clinically meaningful changes in cognitive function over a relatively brief period (i.e., 1 year) in a sample of individuals in the chronic stages of TBI (i.e., x̄ = 6.7 years post-TBI). Thus, the BTACT may be useful in surveillance efforts aimed at understanding and detecting decline, particularly in situations where in-person cognitive screening is impractical or unfeasible. We also identified potentially modifiable targets for the prevention of post-TBI cognitive decline. These findings can offer insights into treatment goals and preventive strategies for individuals at risk for cognitive decline, as well as help to facilitate early identification efforts.

Increased frequency of light physical activity during midlife and old age buffers against cognitive declines

Although it is well established that moderate-to-vigorous physical activity (MVPA) buffers against declines in cognitive health, less is known about the benefits of light physical activity (LPA). Research on the role of LPA is crucial to advancing behavioral interventions to improve late life health outcomes, including cognitive functioning, because this form of physical activity remains more feasible and amenable to change in old age. Our study examined the extent to which increases in LPA frequency protected against longitudinal declines in cognitive functioning and whether such a relationship becomes pronounced in old age when opportunities for MVPA are typically reduced. We analyzed 9-year data from the national Midlife in the United States Study (n = 2,229; Mage = 56 years, range = 33-83; 56% female) using autoregressive models that assessed whether change in LPA frequency predicted corresponding changes in episodic memory and executive functioning in middle and later adulthood. Increases in LPA frequency predicted less decline in episodic memory (β = 0.06, p = .004) and executive functioning (β = 0.14, p < .001) over the 9-year follow-up period, even when controlling for moderate and vigorous physical activity. Effect sizes for moderate and vigorous physical activity were less than half that observed for LPA. Moderation models showed that, for episodic memory, the benefits of increases in LPA frequency were more pronounced at older ages. Findings suggest that increases in LPA over extended periods of time may help slow age-related cognitive declines, particularly in later life when opportunities for MVPA are often diminished.

Long-Term Effects of the Multicomponent Program BrainProtect® on Cognitive Function: One-Year Follow-Up in Healthy Adults

Background

Age-related neuronal changes impact cognitive integrity, which is a major contributor to health and quality of life. The best strategy to prevent cognitive decline and Alzheimer's disease is still debated.

Objective

To investigate the long-term effects of the eight-week multicomponent training program BrainProtect® on cognitive abilities compared to general health counseling (GHC) in cognitively healthy adults in Germany.

Methods

Healthy adults (age ≥50 years) previously randomized to either GHC (n = 72) or BrainProtect (intervention group, IG, n = 60) for eight-weeks (once weekly, 90 minutes, group-based) underwent a comprehensive neuropsychological test battery and health-related quality of life (HRQoL) evaluation 3- and 12-months after intervention end.

Results

Dropout rates were n = 8 after 3 months and n = 19 after 12 months. No significant long-term effect of BrainProtect was observed for the primary endpoint Consortium to Establish a Registry for Alzheimer's Disease (CERAD-Plus) total score. Logical reasoning was significantly improved (p = 0.024) 12 months after completion of the training program in IG participants compared to the GHC group independent of sex, age, education, diet, and physical activity. In IG participants, thinking flexibility (p = 0.019) and confrontational naming (p = 0.010) were improved 3 months after completing the intervention compared to the GHC group, however, after conservative Bonferroni adjustment, significance was lost.

Conclusions

BrainProtect® independently improved logical reasoning compared to GHC up to 12 months after cognitive training's end in healthy adults. To uncover the long-term clinical significance of multicomponent cognitive training in healthy adults, studies with larger sample size and frequent follow up visits are necessary.

Executive functioning in early and middle age adult patients operated for epidural hematoma: A comparative study

Epidural Hematoma (EDH) is a common condition of traumatic brain injury. It has a good prognosis if prompt surgical intervention is conducted. There is a dearth of studies on neuropsychological assessment of executive functioning exclusively in post-operative EDH patients. Moreover, age as a variable in determining executive functions in patients post-head injury, has been studied mostly in the older adults. This cross-sectional case-control study assessed Executive Functions (EF) in 62 post-surgery patients with EDH and compared 57 healthy controls (HC) using standardized assessment tools of sustained attention, speed, working memory, fluency, set-shifting, perseveration, planning, and response inhibition. Further, executive functions in two phases of adulthood, viz. Early Adulthood (20-39 years) and Middle Adulthood (40-60 years) were compared in the EDH group (E-EDH and M-EDH) and HC (E-HC and M-HC). A two-way Analysis of Variance (ANOVA) and correlational analysis was conducted. Results showed a trend where the M-EDH group performed significantly poorer on executive function tests (viz a viz., time taken, errors, and correct responses), followed by E-EDH, M-HC, and E-HC. The main effect of age was found significant on Digit Symbol, Color Trail 1, N-Back 2, Animal Naming, and Stroop Effect (p < 0.01 level) while N-Back 1, WCST-PE, and Tower of London (p < 0.05 level). The findings have significant clinical and therapeutic implications. In addition, it gives guidance regarding planning specific neuropsychological tests and rehabilitation targeting specific areas of executive functions decline due to age in EDH post-surgery patients.

The 'middle-aging' brain

Middle age has historically been an understudied period of life compared to older age, when cognitive and brain health decline are most pronounced, but the scope for intervention may be limited. However, recent research suggests that middle age could mark a shift in brain aging. We review emerging evidence on multiple levels of analysis indicating that midlife is a period defined by unique central and peripheral processes that shape future cognitive trajectories and brain health. Informed by recent developments in aging research and lifespan studies in humans and animal models, we highlight the utility of modeling non-linear changes in study samples with wide subject age ranges to distinguish life stage-specific processes from those acting linearly throughout the lifespan.

Resting EEG Periodic and Aperiodic Components Predict Cognitive Decline Over 10 Years

Measures of intrinsic brain function at rest show promise as predictors of cognitive decline in humans, including EEG metrics such as individual α peak frequency (IAPF) and the aperiodic exponent, reflecting the strongest frequency of α oscillations and the relative balance of excitatory/inhibitory neural activity, respectively. Both IAPF and the aperiodic exponent decrease with age and have been associated with worse executive function and working memory. However, few studies have jointly examined their associations with cognitive function, and none have examined their association with longitudinal cognitive decline rather than cross-sectional impairment. In a preregistered secondary analysis of data from the longitudinal Midlife in the United States (MIDUS) study, we tested whether IAPF and aperiodic exponent measured at rest predict cognitive function (N = 235; age at EEG recording M = 55.10, SD = 10.71) over 10 years. The IAPF and the aperiodic exponent interacted to predict decline in overall cognitive ability, even after controlling for age, sex, education, and lag between data collection time points. Post hoc tests showed that "mismatched" IAPF and aperiodic exponents (e.g., higher exponent with lower IAPF) predicted greater cognitive decline compared to "matching" IAPF and aperiodic exponents (e.g., higher exponent with higher IAPF; lower IAPF with lower aperiodic exponent). These effects were largely driven by measures of executive function. Our findings provide the first evidence that IAPF and the aperiodic exponent are joint predictors of cognitive decline from midlife into old age and thus may offer a useful clinical tool for predicting cognitive risk in aging.

Child support grant expansion and cognitive function among women in rural South Africa: Findings from a natural experiment in the HAALSI cohort

BACKGROUND

Cash transfers are a promising but understudied intervention that may protect cognitive function in adults. Although South Africa has a rapidly ageing population, little is known about the nature of association between cash transfers and cognitive function in this setting.

OBJECTIVES

We leveraged age-eligibility expansions to South Africa's Child Support Grant (CSG) to investigate the association between duration of CSG eligibility and cognitive function of biological mothers of child beneficiaries in South Africa.

METHODS

We analysed 2014/2015 baseline data from 944 women, aged 40-59 years with at least one CSG-eligible child, enrolled in the population-representative HAALSI cohort in Agincourt, South Africa. Duration of CSG eligibility for each mother was calculated based on the birth dates of all their children and the CSG age-eligibility expansion years (2003-2012). Cognitive function was measured using a cognitive battery administered at the HAALSI baseline interview. Linear regression was used to estimate the association between duration of CSG eligibility, dichotomized as low (≤10 years) and high (>10 years) eligibility, and cognitive function z-scores of the mothers.

RESULTS

High vs. low duration of CSG eligibility, was associated with higher cognitive function z-scores in the full sample [β: 0.15 SD units; 95% CI: 0.04, 0.26; p-value = 0.01]. In mothers with one to four lifetime children, but not five or more, high vs. low duration of CSG eligibility, was associated with higher cognitive function z-scores [β: 0.19 SD units; 95% CI: 0.05, 0.34, p-value = 0.02].

CONCLUSION

Government cash transfers given to support raising children may confer substantial protective effects on the subsequent cognitive function of mothers. Further studies are needed to understand how parity may influence this relationship. Our findings bring evidence to policymakers for designing income supplementation programmes to promote healthy cognitive ageing in low-income settings.

Biopsychosocial contexts influence adult cognitive function concurrently and longitudinally

Background

Cognitive aging is a complex process that impacts human behavior. Identifying the factors that preserve cognitive functioning is a public health priority, given that 20% of the US population will be at least 65 years old in the next decade. Biopsychosocial determinants of cognitive decline across the lifespan are often examined as ecological factors that independently moderate cognitive aging, despite the known complexity surrounding these relationships.

Objective

We aimed to address this gap by exploring the synergistic and simultaneous relationship between risk and protective factors on cognitive functioning.

Method

Using the MIDUS study datasets, we examined the relationships among physiological markers, friendship quality, and global cognition functioning, concurrently and longitudinally over ten years. Our participants included 929 healthy (417 men, 512 women) adults (average age at Time 1: 54.6 ± 11.6 years). Exploratory analyses examining the effects of racial minority status were also conducted.

Results

Cross-sectionally, age, and friendship quality moderated the relationship between vagally-mediated heart rate variability (vm-HRV) and cognition such that younger adults with greater friendship quality had a negative relationship between vm-HRV and cognitive performance; our unexpected finding suggests the heart-brain relationship is sensitive to the biopsychosocial environment. Longitudinally, higher IL-6 levels at Time 1 predicted poorer cognitive performance a decade later, but only among those with greater levels of friendship quality, especially for white-identifying individuals.

Conclusions

The relationships among physiological risk factors, social protective factors and cognitive functioning appear to be temporally different during mid-adulthood. Given many of the whole sample findings were not replicated within the racial minority subgroup, we suggest that these relationships should be examined in a larger and more diverse racial minority sample to determine whether this study lacked the power necessary to detect a relationship or if the relationships are in fact different by racial minority sub-group. In addition, future research should overcome the study's reliance on healthy adults and self-report measures of friendship quality by including adults with pre-existing cognitive impairments, and employing more real-time measures of friendship quality, such as daily diary or ecological momentary assessment.

Emotion regulation shows an age- and sex-specific moderating effect on the relationship between chronic stress and cognitive performance

Despite the extensive knowledge about the effects of chronic stress on cognition, the underlying mechanisms remain unclear. We conducted a cross-sectional moderation analysis on a population-based sample of 596 adults to examine the age- and sex-specific role of emotion regulation (ER) in the relationship between chronic stress and cognitive performance using validated self-report questionnaires. While women showed no direct or moderated relationship between stress and cognition, men displayed a distinct age-related pattern where stress was negatively associated with poorer cognitive performance at older ages, and the onset of this relationship was detected earlier in men with ER problems. These results showed that suppression of emotions and lack of executive control of ER amplify the negative consequences of chronic stress and suggest that there are sex-specific differences in the decline of ability to cope with long-term exposure to stressors.

Resting EEG Periodic and Aperiodic Components Predict Cognitive Decline Over 10 Years

Measures of intrinsic brain function at rest show promise as predictors of cognitive decline in humans, including EEG metrics such as individual alpha peak frequency (IAPF) and the aperiodic exponent, reflecting the strongest frequency of alpha oscillations and the relative balance of excitatory:inhibitory neural activity, respectively. Both IAPF and the aperiodic exponent decrease with age and have been associated with worse executive function and working memory. However, few studies have jointly examined their associations with cognitive function, and none have examined their association with longitudinal cognitive decline rather than cross-sectional impairment. In a preregistered secondary analysis of data from the longitudinal Midlife in the United States (MIDUS) study, we tested whether IAPF and aperiodic exponent measured at rest predict cognitive function (N = 235; age at EEG recording M = 55.10, SD = 10.71) over 10 years. The IAPF and the aperiodic exponent interacted to predict decline in overall cognitive ability, even after controlling for age, sex, education, and lag between data collection timepoints. Post-hoc tests showed that "mismatched" IAPF and aperiodic exponents (e.g., higher exponent with lower IAPF) predicted greater cognitive decline compared to "matching" IAPF and aperiodic exponents (e.g., higher exponent with higher IAPF; lower IAPF with lower aperiodic exponent). These effects were largely driven by measures of executive function. Our findings provide the first evidence that IAPF and the aperiodic exponent are joint predictors of cognitive decline from midlife into old age and thus may offer a useful clinical tool for predicting cognitive risk in aging.

Heart Rate Variability and Cognition: A Narrative Systematic Review of Longitudinal Studies

BACKGROUND

Heart rate variability (HRV) is a reliable and convenient method to assess autonomic function. Cross-sectional studies have established a link between HRV and cognition. Longitudinal studies are an emerging area of research with important clinical implications in terms of the predictive value of HRV for future cognition and in terms of the potential causal relationship between HRV and cognition. However, they have not yet been the objective of a systematic review. Therefore, the aim of this systematic review was to investigate the association between HRV and cognition in longitudinal studies.

METHODS

The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Embase, PsycINFO and PubMed databases were searched from the earliest available date to 26 June 2023. Studies were included if they involved adult human subjects and evaluated the longitudinal association between HRV and cognition. The risk of bias was assessed with the Newcastle-Ottawa Scale for Cohort Studies. The results were presented narratively.

RESULTS

Of 14,359 records screened, 12 studies were included in this systematic review, with a total of 24,390 participants. Two thirds of the studies were published from 2020 onwards. All studies found a longitudinal relationship between HRV and cognition. There was a consistent association between higher parasympathetic nervous system (PNS) activity and better cognition, and some association between higher sympathetic nervous system activity and worse cognition. Also, higher PNS activity persistently predicted better executive functioning, while data on episodic memory and language were more scant and/or controversial.

CONCLUSIONS

Our results support the role of HRV as a biomarker of future cognition and, potentially, as a therapeutic target to improve cognition. They will need confirmation by further, more comprehensive studies also including unequivocal non-HRV sympathetic measures and meta-analyses.

Protective roles of meditation practice and self-esteem on cognitive functions over time: findings from the Midlife in the United States study

BACKGROUND

Cognitive function is an important component of healthy ageing. However, it is unclear whether relaxation/meditation practices provide cognitive benefits, particularly in midlife and early late life. Meditative practices are associated with higher self-esteem, and self-esteem serves as a general protective factor for many health outcomes. The current study examines associations between meditation practice, self-esteem, and change over 10 years in midlife cognitive performance.

METHODS

Data were from waves 2 (2003-2004) and 3 (2013-2014) of the Midlife in the United States (MIDUS) study. We used structural equation modelling to examine whether persistent meditation practice at both waves or episodic practice at one wave is associated with better cognitive function over 10 years, compared to no meditation practice, while controlling for prior cognitive function and covariates (baseline socio-demographics, health, and functional status). Additionally, we assessed if self-esteem mediates the above associations.

RESULTS

We included 2168 individuals (Mage  = 65 ± 11). After controlling for covariates, the findings revealed that persistent meditation practice in both waves was associated with significantly less decline in episodic memory; however, no such effects were found for executive function. Further, although participants' higher self-esteem was significantly associated with less decline in executive function and episodic memory, it did not mediate the associations between meditation practice and cognitive functions.

CONCLUSIONS

While both persistent meditation practice and self-esteem have associations with cognitive outcomes for middle-aged and older adults in MIDUS, self-esteem as a mediator was not supported. Thus, future investigations should examine mechanisms that underlie these protective factors on cognitive performances across adulthood.

Is Use of Psychedelic Drugs a Risk or Protective Factor for Late-Life Cognitive Decline?

Objectives: Common age-related health conditions can lead to poor mental health outcomes and deteriorate cognition. Additionally, commonly prescribed medications for various mental/physical health conditions may cause adverse reactions, especially among older adults. Psychedelic therapy has shown positive impacts on cognition and has been successful in treating various mental health problems without long-lasting adversities. The current study examines the association between psychedelic drug usage and cognitive functions in middle-aged and older adults. Methods: Data were from wave 3 (2013-2014) of the Midlife in the United States (MIDUS) study. We used multiple linear regression models examining associations between psychedelic usage and cognitive functions, controlling for covariates of sociodemographic and health factors. Results: We included 2,503 individuals (Mage = 64 ± 11). After controlling for covariates, the finding revealed that psychedelic usage was independently associated with more favorable changes in executive function (β = .102, SE = 0.047, p = .031) and less depressive symptoms (β = -.090, SE = 0.021, p < .001). The same effect was not found for episodic memory (β = .039, SE = 0.066, p = .553). Discussion: Addressing the mental health implications of physical health conditions in older adults are vital for preventing neurocognitive deterioration, prolonging independence, and improving the quality of life. More longitudinal research is essential utilizing psychedelics as an alternative therapy examining late-life cognitive benefits.

Cognitive Speed in Neurodegenerative Disease: Comparing Mean Rate and Inconsistency Within and Across the Alzheimer's and Lewy Body Spectra in the COMPASS-ND Study

Background

Alzheimer's disease (AD) and Lewy body disease (LBD) are characterized by early and gradual worsening perturbations in speeded cognitive responses.

Objective

Using simple and choice reaction time tasks, we compared two indicators of cognitive speed within and across the AD and LBD spectra: mean rate (average reaction time across trials) and inconsistency (within person variability).

Methods

The AD spectrum cohorts included subjective cognitive impairment (SCI, n = 28), mild cognitive impairment (MCI, n = 121), and AD (n = 45) participants. The LBD spectrum included Parkinson's disease (PD, n = 32), mild cognitive impairment in PD (PD-MCI, n = 21), and LBD (n = 18) participants. A cognitively unimpaired (CU, n = 39) cohort served as common benchmark. We conducted multivariate analyses of variance and discrimination analyses.

Results

Within the AD spectrum, the AD cohort was slower and more inconsistent than the CU, SCI, and MCI cohorts. The MCI cohort was slower than the CU cohort. Within the LBD spectrum, the LBD cohort was slower and more inconsistent than the CU, PD, and PD-MCI cohorts. The PD-MCI cohort was slower than the CU and PD cohorts. In cross-spectra (corresponding cohort) comparisons, the LBD cohort was slower and more inconsistent than the AD cohort. The PD-MCI cohort was slower than the MCI cohort. Discrimination analyses clarified the group difference patterns.

Conclusions

For both speed tasks, mean rate and inconsistency demonstrated similar sensitivity to spectra-related comparisons. Both dementia cohorts were slower and more inconsistent than each of their respective non-dementia cohorts.

Impact of Optimism on Cognitive Performance of People Living in Rural Area: Findings From a 20-Year Study in US Adults

Objectives: Mid- or early-late-life cognitive function is an indicator for developing late-life dementia. However, it is still unclear whether rural/urban living contexts provide cognitive benefits across adulthood. Further, higher optimism serves as a general protective factor for many health outcomes. The present study examines associations between rurality/urbanicity, optimism, and change in mid/late-life cognitive functions over time. Methods: Data were from waves 1 to 3 (1995-2015) of the Midlife in the United States (MIDUS) study (N = 2,507). Structural equation models examine whether long-term rural living across both waves (1-2) or intermittent rural living at one wave is associated with better cognitive function over 20 years, compared to no rural living, while controlling for prior cognitive function and covariates (baseline socio-demographics, health, and functional status). Additionally, we assessed if optimism mediates the above associations. Results: After controlling for covariates, long-term rural living (waves 1-2) was indirectly (through less optimism) associated with significantly lower levels of cognitive executive function and episodic memory in wave 3. Conclusions: While long-term rural living and cognitive outcomes have no direct association for MIDUS middle-aged and older adults, mediating roles of optimism in these associations were evident. Future investigations could examine mechanisms that underlie these risk/protective factors on late-life cognition.

Midlife sensory and motor functions improve long-term predictions of cognitive decline and incidence of cognitive impairment

INTRODUCTION

We aimed to assess whether midlife sensory and motor functions improve risk prediction of 10-year cognitive decline and impairment when added to risk prediction models using the Cardiovascular Risk Factors, Aging, and Incidence of Dementia Score (CAIDE) and Framingham Risk Score (FRS).

METHODS

Longitudinal data of N = 1529 (mean age 49 years; 54% women) Beaver Dam Offspring Study (BOSS) participants from baseline, 5 and 10-year follow-up were included. We tested whether including baseline sensory (hearing, vision, olfactory) impairment and motor function improves CAIDE or FRS risk predictions of 10-year cognitive decline or cognitive impairment incidence using logistic regressions.

RESULTS

Adding sensory and motor measures to CAIDE-only and FRS-only models significantly improved areas under the curve for cognitive decline and impairment models.

DISCUSSION

Including midlife sensory and motor function improved risk predictions of long-term cognitive decline and impairment in middle-aged to older adults. Sensory and motor assessments could contribute to cost-effective and non-invasive screening tools that identify high-risk individuals earlier to target intervention and prevention strategies.

Highlights

Sensory and motor measures improve risk prediction models of cognitive decline.Sensory and motor measures improve risk prediction models of cognitive impairment.Prediction improvements were strongest in midlife (adults < 55 years of age).Sensory and motor changes may help identify high-risk individuals early.

Frailty and Processing Speed Performance at the Cusp of Midlife in CATSLife

OBJECTIVES

Frailty is not an end state of aging, but rather represents physiological vulnerability across multiple systems that unfolds across adulthood. However, examinations of frailty at the midlife transition, and how frailty may impact other age-sensitive traits, such as processing speed (PS), remain scarce. Our research aims were to examine frailty and frailty-speed associations before midlife, a ripe developmental period for healthy aging interventions.

METHODS

Using data from the Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging (N = 1,215; Mage = 33.23 years; standard deviation = 4.98), we constructed 25-item (FI25) and 30-item (FI30) frailty indices. PS was measured using the Colorado Perceptual Speed task and WAIS-III Digit Symbol (DS) subtest. Multilevel models accounted for clustering among siblings and adjusted for sex, race, ethnicity, adoption status, educational attainment, and age.

RESULTS

Reliability of FI measures was apparent from strong intraclass correlations (ICCs) among identical twin siblings, although ICC patterns across all siblings suggested that FI variability may include nonadditive genetic contributions. Higher FI was associated with poorer PS performance but was significant for DS only (BFI25 = -1.17, p = .001, d = -0.12; BFI30 = -1.21, p = .001, d = -0.12). Furthermore, the negative frailty-DS association was moderated by age (BFI25×age = -0.14, p = .042; BFI30×age=-0.19, p = .008) where increasingly worse performance with higher frailty emerged at older ages.

DISCUSSION

Frailty is evident before midlife and associated with poorer PS, an association that magnifies with age. These findings help elucidate the interrelationship between indicators of frailty and cognitive performance for adults approaching midlife, an understudied period within life-span development.

The Healthy Caregiver? A Positive Impact of Informal Caregiving Status on Cognitive Functions Over Time From the Midlife in the United States Study

OBJECTIVES

The current study examined whether informal caregivers performed worse, better, or similar to non-caregivers on cognitive tests of executive functioning and episodic memory over 10 years. Methods: Data were from waves 2 (2003-04) and 3 (2013-14) of the Midlife in the United States (MIDUS) study (N = 2086). Multiple linear regression models examined whether caregiving at both waves 2 and 3 predicted better cognitive functioning at wave 3, than caregiving at only one time point or no caregiving (reference) while controlling for baseline covariates (i.e., sociodemographic, health, and functional status).

RESULTS

After controlling for covariates, caregiving at both waves was independently associated with better performance in episodic memory (b = .24, SE = .10, p = .013) but not executive function (b = -.06, SE = .05, p = .246). Discussion:The findings partially supported both healthy caregiver and stress process models, indicating caregiving may be associated with better episodic memory but not executive functioning over time among the middle-aged and older adults.

Neighborhood Cohesion Across the Life Course and Effects on Cognitive Aging

OBJECTIVES

Greater neighborhood cohesion is associated with better cognitive function in adulthood and may serve as a protective factor against cognitive impairment and decline. We build on prior work by examining the effects of perceived neighborhood cohesion across the life course on level and change in cognitive function in adulthood.

METHODS

Utilizing longitudinal data from the Health and Retirement Study (1998-2016) and its Life History Mail Survey, we leveraged data from 3,599 study participants (baseline age: 51-89) who participated in up to 10 waves. Respondents provided retrospective ratings of neighborhood cohesion at childhood (age 10), young adulthood (age at the first full-time job), early midlife (age 40), and concurrently at baseline (i.e., late midlife/adulthood); they completed the modified version of the Telephone Interview for Cognitive Status. We fit a univariate latent growth curve model of change in cognitive function across waves and tested whether neighborhood cohesion during each recollected life stage predicted level and change in cognitive function.

RESULTS

Greater neighborhood cohesion during childhood and late midlife/adulthood each predicted higher cognitive function at baseline but not the rate of cognitive decline. The final model showed that greater neighborhood cohesion in childhood and in late midlife/adulthood remained significantly associated with higher baseline cognitive function, even after accounting for one another.

DISCUSSION

Findings provide insight into life-course neighborhood contextual influences on cognitive aging. Our results emphasize the need for more research to understand the life-course dynamics between neighborhood environments and cognitive aging.

Sense of Control Mediates the Relation between Discrimination and Executive Functions in Middle-Aged and Older Adults: A Structural Equation Modeling Approach

BACKGROUND

Despite previous findings of a negative association between everyday discrimination and executive functions (EF) - a set of domain-general cognitive control processes - in middle-aged and older adults, less is known about the underlying mechanism. Thus, we focused on sense on control and its two facets - perceived constraints and personal mastery - as potential psychosocial mediators of this relation.

METHODS

By analyzing a nationally representative adult cohort from the Midlife Development in the United States (MIDUS) 2 study, we examined two mediational models: a single mediation model with sense of control and a parallel mediation model with perceived constraints and personal mastery as mediators.

RESULTS

Structural equation modeling analyses showed that sense of control, as well as personal mastery and perceived constraints, mediated the relationship between discrimination and EF in middle-aged and older adults. This held true when we controlled for age, race, gender, education, and health status.

CONCLUSION

Our findings underscore the unique and distinctive roles of sense of control and its two facets in the relation between everyday discrimination and EF in middle-aged and older adults.

Long-term Multidomain Patterns of Change After Traumatic Brain Injury: A TRACK-TBI LONG Study

BACKGROUND AND OBJECTIVES

Traumatic brain injury (TBI) may be a chronic condition carrying risk of future sequelae; few prospective studies examine long-term postinjury outcomes. We examined the prevalence of functional, cognitive, and psychiatric change outcomes from 1 to 7 years postinjury.

METHODS

Transforming Research and Clinical Knowledge in TBI LONG (TRACK-TBI LONG) participants were prospectively enrolled within 24 hours of injury and followed up to 1 year postinjury; a subset participated in long-term follow-up from 2 to 7 years postinjury. Reliable change thresholds for the Brief Test of Adult Cognition by Telephone General Composite (cognition) and Brief Symptom Inventory (BSI)-18 (psychiatric) were derived from orthopedic trauma controls (OTCs). Multiple assessments were completed (postinjury baseline assessment and 2 or 3 visits 2-7 years postinjury) within a sample subset. Change was assessed for functional outcome (Glasgow Outcome Scale-Extended [GOSE]) and self-report/informant report of decline. Prevalence ratios for outcomes classified as stable, improved, and declined were reported individually and collectively. The Fisher exact test and log-binomial regression models examined factors associated with decline and improvement.

RESULTS

Of the sample (N = 1,264; mild TBI [mTBI], Glasgow Coma Scale [GCS] 13-15, n = 917; moderate-to-severe TBI [msTBI], GCS 3-12, n = 193; or OTC n = 154), "stable" was the most prevalent outcome. Functional outcome showed the highest rates of decline, regardless of TBI severity (mild = 29%; moderate/severe = 23%). When measures were collectively considered, rates of decline included mTBI (21%), msTBI (26%), and OTC (15%). Age and preinjury employment status were associated with functional decline (per 10 years; relative risk [RR] 1.16, 95% CI 1.07-1.25, p < 0.001; higher in retired/disabled/not working vs full-time/part-time; RR 1.81, 95% CI 1.33-2.45, respectively) in the mTBI group. Improvement in functional recovery 2-7 years postinjury was associated with higher BSI scores (per 5 points; RR 1.11, 95% CI 1.04-1.18, p = 0.002) and GOSE score of 5-7 (GOSE = 8 as reference; RR 2.64, 95% CI 1.75-3.97, p < 0.001). Higher BSI scores and identifying as Black (RR 2.28, 95% CI 1.59-3.25, p < 0.001) were associated with a greater likelihood of improved psychiatric symptoms in mTBI (RR 1.21, 95% CI 1.14-1.29, p < 0.001). A greater likelihood of cognitive improvement was observed among those with higher educational attainment in msTBI (per 4 years; RR 2.61, 95% CI 1.43-4.79, p = 0.002).

DISCUSSION

Function across domains at 1-year postinjury, a common recovery benchmark, undergoes change across the subsequent 6 years. Results support consideration of TBI as a chronic evolving condition and suggest continued monitoring, rehabilitation, and support is required to optimize long-term independence and quality of life.

Incorporation of concussion history as part of the LIfestyle for BRAin Health (LIBRA) modifiable factors risk score and associations with cognition in older former National Football League players

OBJECTIVE

Investigate associations between the LIfestyle for BRAin Health (LIBRA) risk score with odds of mild cognitive impairment (MCI) diagnosis and cognitive function, incorporating concussion history.

METHODS

Former National Football League (NFL) players (N = 1050; mean age = 64.8 ± 9.0-years) completed initial testing for integration of concussion history into LIBRA scores (i.e., modified-LIBRA) and completed the Brief Test of Adult Cognition by Telephone (BTACT). Modified-LIBRA score (including concussion history) associations with odds of MCI and cognitive dysfunction were assessed via logistic and linear regression.

RESULTS

The highest quartile LIBRA scores were six times more likely to have a diagnosis of MCI compared to the lowest quartile (OR = 6.27[3.61, 10.91], p < 0.001). Modified-LIBRA scores significantly improved model fit for odds of MCI above original LIBRA scores (χ2 (1) = 7.76, p = 0.005) and accounted for a greater fraction of variance in executive function (ΔR2  = 0.02, p = 0.003) and episodic memory (ΔR2  = 0.02, p = 0.002).

CONCLUSIONS

Modified-LIBRA score, incorporating concussion history, may help monitoring risk status in former contact sport athletes, by targeting modifiable, lifestyle-related risk factors.

Executive function performance in middle-aged adults

Executive functions have been widely studied in the extreme of ages, but studies in middle-aged adults remain largely neglected. Education and gender are known to influence cognitive performance; however, their effect on executive function in middle-aged adults remains unclear.

Objective

The study aimed to observe the effect of hierarchy of educational qualifications (graduate, postgraduate, and PhD) and gender on various executive function tests across middle-aged adults with or without comorbidity.

Methods

A total of 66 middle-aged individuals volunteered for the study (mean age=48.45±5.45 years; 20 graduates, 28 postgraduates, and 18 PhD; 36 males and 30 females; 38 healthy adults and 28 adults with comorbidities). Each subject performed a test assessing short-term memory, spatial working memory, and multitasking abilities on the Cambridge Neuropsychological Test Automated Battery with rest periods in no specific order of tests. Key parameters of cognitive tests were analyzed for differences in educational qualifications (ANOVA), gender (t-test), and the effect of comorbidity as a covariate (ANCOVA).

Results

PhDs performed significantly better (p<0.05) in multitasking than graduates and had superior visuospatial working memory (fewer errors). Differences in simultaneous matching abilities, lower incongruence cost and multitasking cost were statistically significant in healthy females than in males.

Conclusion

On considering adults with comorbidity, those with higher educational attainment retained the ability to multitask compared to their healthy counterparts, which was not seen in the group with lower educational attainment. Thus, higher educational attainment attenuated the influence of comorbidities and deterioration of executive functions in general in middle-aged adults.

Long-Term Outcome of Clozapine in Treatment-Resistant Schizophrenia

PURPOSE/BACKGROUND

The favorable effect of clozapine on psychotic symptoms in patients with treatment-resistant (TR) schizophrenia (SCZ) in short-term studies is well established. However, prospective studies of the long-term outcome of clozapine treatment on psychopathology, cognition, quality of life, and functional outcome in TR-SCZ are limited.

METHODS/PROCEDURES

Here, we have examined the long-term (mean duration of follow-up 14 years) effects of clozapine on those outcomes in a prospective, open label study in 54 TR-SCZ patients. Assessments were performed at baseline, 6 weeks, 6 months, and at the last follow-up.

FINDINGS/RESULTS

Brief Psychiatric Rating Scale (BPRS) total, positive symptoms, and anxiety/depression at the last follow-up improved significantly from baseline, as well as from the 6-month evaluation ( P < 0.0001), with a 70.5% responder rate (≥20% improvement at the last follow-up from baseline). Quality of Life Scale (QLS) total improved by 72% at the last follow-up, with 24% of patients rated as having "good" functioning compared with 0% at baseline. Suicidal thoughts/behavior was significantly reduced at the last follow-up from the baseline. No significant change in negative symptoms was found at the last follow-up in the total sample. Short-term memory function declined at the last follow-up from baseline, but there was no significant change in processing speed. The QLS total showed a significant negative correlation with BPRS positive symptoms but not with cognitive measures, or negative symptoms, at the last follow-up.

IMPLICATIONS/CONCLUSIONS

For patients with TR-SCZ, improving psychotic symptoms with clozapine seems to have a more significant impact than negative symptoms or cognition on improving psychosocial function.

Age-Related Changes in Episodic Processing of Scenes: A Functional Activation and Connectivity Study

The posterior-to-anterior shift in aging (PASA) effect is seen as a compensatory model that enables older adults to meet increased cognitive demands to perform comparably as their young counterparts. However, empirical support for the PASA effect investigating age-related changes in the inferior frontal gyrus (IFG), hippocampus, and parahippocampus has yet to be established. 33 older adults and 48 young adults were administered tasks sensitive to novelty and relational processing of indoor/outdoor scenes in a 3-Tesla MRI scanner. Functional activation and connectivity analyses were applied to examine the age-related changes on the IFG, hippocampus, and parahippocampus among low/high-performing older adults and young adults. Significant parahippocampal activation was generally found in both older (high-performing) and young adults for novelty and relational processing of scenes. Younger adults had significantly greater IFG and parahippocampal activation than older adults, and greater parahippocampal activation compared to low-performing older adults for relational processing-providing partial support for the PASA model. Observations of significant functional connectivity within the medial temporal lobe and greater negative left IFG-right hippocampus/parahippocampus functional connectivity for young compared to low-performing older adults for relational processing also supports the PASA effect partially.

Effects of Pension Eligibility Expansion on Men's Cognitive Function: Findings from Rural South Africa

Two-thirds of people living with Alzheimer's disease and related dementias (ADRD) live in low- and middle-income countries, and this figure is expected to rise as these populations are rapidly aging. Since evidence demonstrates links between socioeconomic status and slower rates of cognitive decline, protecting older adults' cognitive function in resource-limited countries that lack the infrastructure to cope with ADRD is crucial to reduce the burden it places on these populations and their health systems. While cash transfers are a promising intervention to promote healthy cognitive aging, factors such as household wealth and level of education often confound the ability to make causal inferences on the impact of cash transfers and cognitive function. This study uses a quasi-experimental design, leveraging an exogenous expansion to the Old Age Pension for men in South Africa, to approximate causal associations with cognitive function. We found evidence that there is a potential benefit of cash transfers at an earlier age for older individuals. As such, transfers such as pensions or other forms of direct basic income transfers may hold promise as potential interventions to promote healthy cognitive aging.

MidCog study: a prospective, observational cohort study investigating health literacy, self-management skills and cognitive function in middle-aged adults

INTRODUCTION

The lack of definitive means to prevent or treat cognitive impairment or dementia is driving intense efforts to identify causal mechanisms. Recent evidence suggests clinically meaningful declines in cognition might present as early as middle age. Studying cognitive changes in middle adulthood could elucidate modifiable factors affecting later cognitive and health outcomes, yet few cognitive ageing studies include this age group. The purpose of the MidCog study is to begin investigations of less-studied and potentially modifiable midlife determinants of later life cognitive outcomes.

METHODS AND ANALYSIS

MidCog is a prospective cohort study of adults ages 35-64, with two in-person interviews 2.5 years apart. Data will be collected from interviews, electronic health records and pharmacy fill data. Measurements will include health literacy, self-management skills, cognitive function, lifestyle and health behaviours, healthcare use, health status and chronic disease outcomes. Associations of health literacy and self-management skills with health behaviours and cognitive/health outcomes will be examined in a series of regression models, and moderating effects of modifiable psychosocial factors.Finally, MidCog data will be linked to an ongoing, parallel cohort study of older adults recruited at ages 55-74 in 2008 ('LitCog'; ages 70-90 in 2023), to explore associations between age, health literacy, self-management skills, chronic diseases, health status and cognitive function among adults ages 35-90.

ETHICS AND DISSEMINATION

The Institutional Review Board at Northwestern University has approved the MidCog study protocol (STU00214736). Results will be published in peer-reviewed journals and summaries will be provided to the funders of the study as well as patients.

Child Support Grant expansion and cognitive function among women in rural South Africa: findings from a natural experiment in HAALSI cohort

Cash transfers are a promising but understudied intervention that may protect cognitive function in adults by promoting their cognitive reserve. South Africa has a rapidly ageing population, however, less is known about the nature of association between cash transfers and cognitive function in this setting. We leveraged natural experiments from Child Support Grant (CSG) age-eligibility expansions to investigate the association between duration of CSG eligibility and cognitive function among biological mothers of child beneficiaries in South Africa. We analysed 2014/2015 baseline data from 944 women, aged 40 - 59 years with at least one CSG-eligible child, enrolled in the HAALSI cohort in Agincourt, South Africa. Duration of CSG eligibility for each mother was calculated based on the birth dates of all their children and the CSG age eligibility expansion years. Cognitive function was measured using a cognitive battery administered to the mothers at baseline interview. Linear regression was used to estimate the association between duration of CSG eligibility, dichotomized as low (≤10 years) and high (>10 years) eligibility, and cognitive function z-scores of the mothers. Our study finds that high duration of CSG eligibility, compared to low, was associated with higher cognitive function z-scores in the full sample [β: 0.15 SD; 95% CI: 0.04, 0.26; p-value = 0.01]. In mothers with one to four lifetime children, but not five or more, high duration of CSG eligibility, compared to low, was associated with higher cognitive function z-scores [β: 0.19 SD; 95% CI: 0.05, 0.34, p-value = 0.02]. Government cash transfers given to support raising children may confer substantial protective effect on cognitive function of mothers in their mid-life. Further studies are needed to understand how parity may influence this relationship. Our findings bring evidence to policymakers for designing income supplementation programmes to promote healthy cognitive ageing in low-income settings.

Mind-Body Practice and Family Caregivers' Subjective Well-Being: Findings From the Midlife in the United States (MIDUS) Study

Objectives: Informal caregiving has been associated with higher stress and lower levels of subjective well-being. Mind-body practices including yoga, tai chi, and Pilates also incorporate stress reducing activities. The current study aimed to examine the association between mind-body practice and subjective well-being among informal family caregivers. Methods: A sample of informal caregivers were identified in the Midlife in the United States study (N = 506, M ± SD_age = 56 ± 11, 67% women). We coded mind-body practice into three categories, including regular practice (participating in one or more of them "a lot" or "often"), irregular (participating "sometimes" and "rarely") and no practice ("never"). Subjective well-being was measured using the 5-item global life satisfaction scale and the 9-item mindfulness scale. We used multiple linear regression models to examine associations between mind-body practice and caregivers' subjective well-being, controlling for covariates of sociodemographic factors, health, functional status, and caregiving characteristics. Results: Regular practice was associated with both better mindfulness-related well-being (b = 2.26, p < .05) and better life satisfaction (b = 0.43, p < .05), after controlling for covariates. Discussion: Future research should examine whether there is a selection effect of caregivers with higher well-being being more likely to choose these activities, and/or if mind-body practices are effective non-pharmacological interventions to improve family caregivers' quality of life.

Associations of Midlife Lifestyle and Health Factors with Long-Term Changes in Blood-Based Biomarkers of Alzheimer's Disease and Neurodegeneration

BACKGROUND

Pathological biomarkers of Alzheimer's disease (AD) and other dementias can change decades before clinical symptoms. Lifestyle and health factors might be relevant modifiable risk factors for dementia. Many previous studies have been focusing on associations of lifestyle and health-related factors with clinical outcomes later in life.

OBJECTIVE

We aimed to determine to what extent midlife factors of lifestyle, inflammation, vascular, and metabolic health were associated with long-term changes in blood-based biomarkers of AD (amyloid beta (Aβ)) and neurodegeneration (neurofilament light chain (NfL); total tau(TTau)).

METHODS

In 1,529 Beaver Dam Offspring Study (BOSS) participants (mean age 49 years, standard deviation (SD) = 9; 54% were women), we applied mixed-effects models with baseline risk factors as determinants and 10-year serum biomarker change as outcomes.

RESULTS

We found that education and inflammatory markers were associated with levels and/or change over time across all three markers of AD and neurodegeneration in the blood. There were baseline associations of measures of cardiovascular health with lower Aβ42/Aβ40. TTau changed little over time and was higher in individuals with diabetes. Individuals with lower risk in a number of cardiovascular and metabolic risk factors, including diabetes, hypertension, and atherosclerosis had slower accumulation of neurodegeneration over time, as determined by NfL levels.

CONCLUSION

Various lifestyle and health factors, including education and inflammation, were associated with longitudinal changes of neurodegenerative and AD biomarker levels in midlife. If confirmed, these findings could have important implications for developing early lifestyle and health interventions that could potentially slow processes of neurodegeneration and AD.

Inferring Cognitive Abilities from Response Times to Web-Administered Survey Items in a Population-Representative Sample

Monitoring of cognitive abilities in large-scale survey research is receiving increasing attention. Conventional cognitive testing, however, is often impractical on a population level highlighting the need for alternative means of cognitive assessment. We evaluated whether response times (RTs) to online survey items could be useful to infer cognitive abilities. We analyzed >5 million survey item RTs from >6000 individuals administered over 6.5 years in an internet panel together with cognitive tests (numerical reasoning, verbal reasoning, task switching/inhibitory control). We derived measures of mean RT and intraindividual RT variability from a multilevel location-scale model as well as an expanded version that separated intraindividual RT variability into systematic RT adjustments (variation of RTs with item time intensities) and residual intraindividual RT variability (residual error in RTs). RT measures from the location-scale model showed weak associations with cognitive test scores. However, RT measures from the expanded model explained 22−26% of the variance in cognitive scores and had prospective associations with cognitive assessments over lag-periods of at least 6.5 years (mean RTs), 4.5 years (systematic RT adjustments) and 1 year (residual RT variability). Our findings suggest that RTs in online surveys may be useful for gaining information about cognitive abilities in large-scale survey research.

A life course approach to understanding stress exposures and cognitive function among middle-aged and older adults

BACKGROUND

Many studies have evaluated the stress-cognition association, but few have captured the cumulative nature of stress or distinguished the influences of stressors occurring in childhood versus adulthood. Using a lifecourse approach, we investigated whether cumulative stress exposures are associated with poorer cognitive function and faster cognitive decline.

METHODS

We used data from the Midlife Development in the United States Study (N = 3,954, mean baseline age: 56 years). We fit marginal structural generalized estimating equations models to estimate the difference in baseline cognitive function per SD increment in the continuous stressor score, and, separately, between persons in each life course stressor profile and those who did not experience high stress in either childhood or adulthood. We also characterized differences in cognitive decline across levels of stress exposures.

RESULTS

Higher cumulative stress exposure was associated with lower executive function (difference per SD in continuous stressor score = -0.12 SD units, 95% CI = -0.16, -0.08) and episodic memory (difference = -0.09 SD units, 95% CI = -0.13, -0.05). Baseline executive function and episodic memory were lower among those with high stress only in childhood, only in adulthood, and both, than among those without high stress in childhood or adulthood. There was little evidence that rate of change in executive function and episodic memory differed across levels of cumulative stress exposures.

CONCLUSIONS

These findings offer support to the hypothesis that stress exposures, accumulated over the life course, worsen cognitive performance, but limited support for the hypothesis that these exposures promote cognitive decline.

Voice biomarkers as indicators of cognitive changes in middle and later adulthood

Voice prosody measures have been linked with Alzheimer's disease (AD), but it is unclear whether they are associated with normal cognitive aging. We assessed relationships between voice measures and 10-year cognitive changes in the MIDUS national sample of middle-aged and older adults ages 42-92, with a mean age of 64.09 (standard deviation = 11.23) at the second wave. Seven cognitive tests were assessed in 2003-2004 (Wave 2) and 2013-2014 (Wave 3). Voice measures were collected at Wave 3 (N = 2585) from audio recordings of the cognitive interviews. Analyses controlled for age, education, depressive symptoms, and health. As predicted, higher jitter was associated with greater declines in episodic memory, verbal fluency, and attention switching. Lower pulse was related to greater decline in episodic memory, and fewer voice breaks were related to greater declines in episodic memory and verbal fluency, although the direction of these effects was contrary to hypotheses. Findings suggest that voice biomarkers may offer a promising approach for early detection of risk factors for cognitive impairment or AD.

Job demands may determine cognitive and physical aging after retirement

During adulthood, we spend most of our time and efforts at work. However, the impact of employment in aging is poorly explored. Our study addressed how job demands can affect aging after retirement. We have developed a descriptive observational study carried out in 367 older adults with a mean age of 73.9 years (66.5% women and 33.5% men), measuring cognition and functional status. Our results demonstrate that older adults who had high mental demands in their jobs, show better scores in cognition. However, they show poor functional development of basic and instrumental activities of daily life (p< .05). In contrast, former workers who had high physical demands, display lower scores in cognition and lower functional performance in instrumental activities (p< .05). Work life activities contribute to cognitive and physical decline after retirement. Therefore, healthy aging should include interventions that consider the job influence on the age impairment.

Evaluation of Usability and Learning Motivation of e-Learning Courses for People With Chronic Kidney Disease

Nurses need to increase patient education opportunities so that more people with chronic kidney disease can understand the disease accurately from its early stages. We developed an e-learning course based on the Dick and Carey system approach model and the attention, relevance, confidence, satisfaction model for people with chronic kidney disease. People with chronic kidney disease, on average, are aged around 50 to 60 years, and this population tends to lack perceived susceptibility toward and concern for the disease owing to the asymptomatic nature of early chronic kidney disease. Therefore, e-learning should be easy to use and motivate learning. This study aimed to evaluate the usability and learning motivation of this course. The participants included 10 outpatients (mean age, 51.2 years) with chronic kidney disease whose mastery percentage of learning objectives was compared by the knowledge tests immediately before and after the course. We also observed the participants' operation status and measured their motivation for using instructional materials with a questionnaire. The results demonstrated that this course facilitates independent operation, improves postcourse performance, and motivates participants in all areas of learning motivation. Thus, this e-learning course can be recommended as easy to use and motivating for people with chronic kidney disease.

Diurnal dynamic range as index of dysregulation of system dynamics. A cortisol examplar using data from the Study of Midlife in the United States

We discuss the importance of including measures of dysregulated system dynamics in the operationalization of allostatic load. The concept of allostatic load, as originally proposed by McEwen and Stellar, included dysregulation not only in the resting state of physiological systems, but also in system dynamics. We describe previous work on cortisol diurnal dynamic range (peak to nadir spread) as an index of the health of the hypothalamic-pituitary-adrenal axis, with compression of dynamic range being a marker of dysregulation. In particular, we review the evidence for a) diurnal dynamic range compression in people from disadvantaged backgrounds, b) cross-sectional association of cortisol diurnal dynamic range compression with dysregulation in other systems' resting states, and c) cross-sectional association of cortisol diurnal dynamic range compression with lower scores on cognitive testing. Then, we present new data from the Study of Midlife in the United States (MIDUS) on longitudinal associations of cortisol dynamic range compression with subsequent cognitive decline and all-cause mortality. Briefly, each standard deviation decrement in cortisol diurnal dynamic range is associated with adjusted mortality hazard ratio of 1.35 (95% confidence interval: 1.19, 1.54). Among those who scored at median or lower in executive functioning at baseline and survive, each standard deviation decrement in cortisol dynamic range is associated with 1% greater decline in executive functioning over a decade (95% confidence interval: 0.4%, 2.0%). We conclude that including measures of system dynamics like diurnal dynamic range in the next generation of allostatic load measurement will likely advance understanding of the cumulative physiological burden of chronic stress and life experiences, and improve the prediction of future health consequences.

The age differences and effect of mild cognitive impairment on perceptual-motor and executive functions

It is unclear whether the decline in executive function (EF) and perceptual-motor function (PMF) found in older adults with mild cognitive impairment (MCI) is the result of a normal aging process or due to MCI. This study aimed to determine age-related and MCI-related cognitive impairments of the EF and PMF. The EF and PMF were investigated across four groups of 240 participants, 60 in each group, including early adult, middle adult, older adult, and older adult with probable MCI. The EF, working memory, inhibition, and cognitive flexibility were evaluated using digit span backward tasks, the Stroop color-word test, and the modified switching verbal fluency test, respectively. The PMF, visual perception, visuoconstructional reasoning, and perceptual-motor coordination were evaluated using the clock reading test, stick design test, and stick catching test, respectively. Group differences were found for all subdomains of EF and PMF (p < 0.05), except for perceptual-motor coordination, indicating that this subdomain could be maintained in older adults and was not affected by MCI. For the age difference, working memory, cognitive flexibility, visual perception, and visuoconstructional reasoning remained stable across middle adults and started to decline in older adults, while cognitive inhibition began to decrease in middle adults and it further declined in older adults. To control the confounding effect of education level, the results showed that only cognitive flexibility was further decreased in older adults with probable MCI compared to those without MCI (p < 0.05). In conclusion, cognitive inhibition decreased earlier in middle adults, whereas EF and PMF started to decline in older adults. Cognitive flexibility was the only MCI-sensitive cognitive function.

The Mediating Role of Cardiometabolic Dysregulation on the Relation Between Adverse Childhood Experiences and Adult Cognition

OBJECTIVE

Adverse childhood experiences (ACEs) are uncontrollable stressful events during early life that predispose adults to adverse health outcomes, such as impaired cognitive functioning. However, little is known about the factors indirectly impacting this relation. Biological dysregulation may be one pathway that can help explain the relations between ACEs and later cognition. The current study examined the mediating role of cardiometabolic dysregulation on the relation between ACEs and cognition.

METHODS

Our study gathered data from 1053 participants using three waves of the Midlife in the United States longitudinal study. Linear regression analyses and bootstrapped mediation analyses were performed to analyze the direct and indirect associations of cardiometabolic dysregulation on ACEs and cognition.

RESULTS

Our results showed a significant linear relationship between ACEs and cardiometabolic dysregulation ( b = 0.152, standard error [SE] = 0.056, p = .007), and a significant indirect association, such that cardiometabolic dysregulation mediated the relation between ACEs and cognitive status at wave II ( b = -0.007, SE = 0.004, p = .044) and cognitive status at wave III ( b = -0.006, SE = 0.003, p .042). There was no significant direct or indirect relation when cognitive change was the outcome variable.

CONCLUSIONS

The present study identifies a combined biological pathway that connects ACEs to cognition in late life. These findings supports the need to empirically determine biological mechanism that can be used to develop targeted clinical interventions to prevent the progression of chronic cognitive impairment.

Lifespan evolution of neurocognitive impairment in schizophrenia - A narrative review

Cognitive impairment is a well-recognized key feature of schizophrenia. Here we review the evidence on (1) the onset and sensitive periods of change in cognitive impairment before and after the first psychotic episode, and (2) heterogeneity in neurocognitive presentations across cognitive domains between and within individuals. Overall, studies suggest that mild cognitive impairment in individuals who develop schizophrenia or related disorders is already present during early childhood. Cross-sectional studies further suggest increasing cognitive impairments from pre- to post-psychosis onset, with the greatest declines between adolescence, the prodrome, and the first psychotic episode and with some variability between domains. Longitudinal studies with more than 10 years of observation time are scarce but support mild cognitive declines after psychosis onset until late adulthood. Whether and how much this cognitive decline exceeds normal aging, proceeds further in older patients, and is specific to certain cognitive domains and subpopulations of patients remains to be investigated. Finally, studies show substantial heterogeneity in cognitive performance in schizophrenia and suggest a variety of impairment profiles.

This review highlights a clear need for long-term studies that include a control group and individuals from adolescence to old age to better understand critical windows of cognitive change and their predictors. The available evidence stresses the importance of interventions that aim to counter cognitive decline during the prodromal years, as well as careful assessment of cognition in order to determine who will profit most from which cognitive training.

Longitudinal Associations between Personal Growth and Cognitive Functioning in Adulthood

OBJECTIVES

While personal growth has been found to be associated with multiple aspects of health in adulthood, its associations with cognitive functioning have not been fully understood. The present study aimed to assess both directions of such longitudinal associations.

METHOD

Using data from the second wave (T1) and third wave (T2) of the Midlife in the United States (MIDUS) study (N = 4,206; mean age = 56.0 [SD = 12.3]), a longitudinal measurement model containing latent variables of episodic memory and executive function was first constructed. Built on the measurement model, a cross-lagged panel model was analyzed to assess relationships between personal growth and the two areas of cognitive functioning, in which T1 personal growth predicted residualized changes in episodic memory and executive function, and T1 episodic memory and executive function predicted change in personal growth, controlling for covariates.

RESULTS

T1 personal growth significantly predicted smaller decreases in episodic memory, whereas it did not predict change in executive function. T1 episodic memory, but not T1 executive function, significantly predicted smaller decreases in personal growth.

DISCUSSION

The present findings were unique, particularly implying potential longitudinal reciprocity between personal growth and episodic memory. These findings and implications can inform future research aimed at exploring approaches to promoting personal growth and cognitive functioning among aging adults.

Self-administered Web-Based Tests of Executive Functioning and Perceptual Speed: Measurement Development Study With a Large Probability-Based Survey Panel

BACKGROUND

Cognitive testing in large population surveys is frequently used to describe cognitive aging and determine the incidence rates, risk factors, and long-term trajectories of the development of cognitive impairment. As these surveys are increasingly administered on internet-based platforms, web-based and self-administered cognitive testing calls for close investigation.

OBJECTIVE

Web-based, self-administered versions of 2 age-sensitive cognitive tests, the Stop and Go Switching Task for executive functioning and the Figure Identification test for perceptual speed, were developed and administered to adult participants in the Understanding America Study. We examined differences in cognitive test scores across internet device types and the extent to which the scores were associated with self-reported distractions in everyday environments in which the participants took the tests. In addition, national norms were provided for the US population.

METHODS

Data were collected from a probability-based internet panel representative of the US adult population-the Understanding America Study. Participants with access to both a keyboard- and mouse-based device and a touch screen-based device were asked to complete the cognitive tests twice in a randomized order across device types, whereas participants with access to only 1 type of device were asked to complete the tests twice on the same device. At the end of each test, the participants answered questions about interruptions and potential distractions that occurred during the test.

RESULTS

Of the 7410 (Stop and Go) and 7216 (Figure Identification) participants who completed the device ownership survey, 6129 (82.71% for Stop and Go) and 6717 (93.08% for Figure Identification) participants completed the first session and correctly responded to at least 70% of the trials. On average, the standardized differences across device types were small, with the absolute value of Cohen d ranging from 0.05 (for the switch score in Stop and Go and the Figure Identification score) to 0.13 (for the nonswitch score in Stop and Go). Poorer cognitive performance was moderately associated with older age (the absolute value of r ranged from 0.32 to 0.61), and this relationship was comparable across device types (the absolute value of Cohen q ranged from 0.01 to 0.17). Approximately 12.72% (779/6123 for Stop and Go) and 12.32% (828/6721 for Figure Identification) of participants were interrupted during the test. Interruptions predicted poorer cognitive performance (P<.01 for all scores). Specific distractions (eg, watching television and listening to music) were inconsistently related to cognitive performance. National norms, calculated as weighted average scores using sampling weights, suggested poorer cognitive performance as age increased.

CONCLUSIONS

Cognitive scores assessed by self-administered web-based tests were sensitive to age differences in cognitive performance and were comparable across the keyboard- and touch screen-based internet devices. Distraction in everyday environments, especially when interrupted during the test, may result in a nontrivial bias in cognitive testing.

Intergenerational Socioeconomic Mobility and Cognitive Impairment Among Chinese Older Adults: Gender Differences

This study examined the impact of intergenerational socioeconomic mobility on the risk of cognitive impairment in a cohort of Chinese older adults aged 60 years and older. Data were derived from the 2014 wave of the Chinese Longitudinal Healthy Longevity Survey. Logistic regression models were performed to assess the impact of three dimensions of socioeconomic mobility (occupational mobility, educational mobility, and residential mobility) on the risk of cognitive impairment. We found that men who were stable with non-professional jobs across generations had a higher risk of cognitive impairment than their counterparts who experienced upward occupational mobility compared to their father. This pattern was not observed in women. There was little evidence that educational mobility or residential mobility affected cognitive impairment in later life. The findings have implications for advancing supportive policies and practices related to maximizing the benefits of education and career advancements for cognition in later life.

Association of Genetic Variants Linked to Late-Onset Alzheimer Disease With Cognitive Test Performance by Midlife

IMPORTANCE

Identifying the youngest age when Alzheimer disease (AD) influences cognition and the earliest affected cognitive domains will improve understanding of the natural history of AD and approaches to early diagnosis.

OBJECTIVE

To evaluate the age at which cognitive differences between individuals with higher compared with lower genetic risk of AD are first apparent and which cognitive assessments show the earliest difference.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from UK Biobank participants of European genetic ancestry, aged 40 years or older, who contributed genotypic and cognitive test data from January 1, 2006, to December 31, 2015. Data analysis was performed from March 10, 2020, to January 4, 2022.

EXPOSURE

The AD genetic risk score (GRS), which is a weighted sum of 23 single-nucleotide variations.

MAIN OUTCOMES AND MEASURES

Seven cognitive tests were administered via touchscreen at in-person visits or online. Cognitive domains assessed included fluid intelligence, episodic memory, processing speed, executive functioning, and prospective memory. Multiple cognitive measures were derived from some tests, yielding 32 separate measures. Interactions between age and AD-GRS for each of the 32 cognitive measures were tested with linear regression using a Bonferroni-corrected P value threshold. For cognitive measures with significant evidence of age by AD-GRS interaction, the youngest age of interaction was assessed with new regression models, with nonlinear specification of age terms. Models with youngest age of interaction from 40 to 70 years, in 1-year increments, were compared, and the best-fitting model for each cognitive measure was chosen. Results across cognitive measures were compared to determine which cognitive indicators showed earliest AD-related change.

RESULTS

A total of 405 050 participants (mean [SD] age, 57.1 [7.9] years; 54.1% female) were included. Sample sizes differed across cognitive tests (from 12 455 to 404 682 participants). The AD-GRS significantly modified the association with age on 13 measures derived from the pairs matching (range in difference in mean cognition per decade increase in age for 1-SD higher AD-GRS, 2.5%-11.5%), symbol digit substitution (range in difference in mean cognition per decade increase in age for 1-SD higher AD-GRS, 2.0%-5.8%), and numeric memory tests (difference in mean cognition per decade increase in age for 1-SD higher AD-GRS, 8.8%) (P = 1.56 × 10-3). Best-fitting models suggested that cognitive scores of individuals with a high vs low AD-GRS began to diverge by 56 years of age for all 13 measures and by 47 years of age for 9 measures.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, by early midlife, subtle differences in memory and attention were detectable among individuals with higher genetic risk of AD.