Episodic Memory Performance Research Articles

Immune cell counts in cerebrospinal fluid predict cognitive function in aging and neurodegenerative disease.

Immune dysfunction is important in aging and neurodegeneration; lacking clinically available tools limits research translation. We tested associations of cerebral spinal fluid (CSF) monocyte-to-lymphocyte ratio (MLR)-innate immune activation surrogate-with cognition in an aging and dementia cohort, hypothesizing that elevated MLR is associated with poorer executive functioning. CSF MLR was calculated in well-characterized, genotyped participants enrolled in studies of aging and dementia at University of California, San Francisco Memory and Aging Center (n=199, mean age 57.5 years, SD 11.9). Linear models tested associations with episodic memory and executive function (verbal fluency, speeded set-shifting). Aging was associated with higher CSF monocyte, lower lymphocyte counts, and higher MLRs (p<0.001). MLR was associated with verbal fluency (p<0.05) only. Using clinical labs, we show an inverse association between CSF MLR and executive function in aging and dementia, supporting the utility of clinical labs in capturing associations between innate immune dysfunction and neurodegeneration.

Cannabis use and episodic memory performance among adolescents: Moderating effects of depression symptoms and sex.

Cannabis use has been linked to poorer episodic memory. However, little is known about whether depression and sex may interact as potential moderators of this association, particularly among adolescents. The current study addresses this by examining interactions between depression symptoms and sex on the association between cannabis use and episodic memory in a large sample of adolescents. Cross-sectional data from 360 adolescents (M age = 17.38, SD = .75) were analyzed at the final assessment wave of a two-year longitudinal study. We used the Drug Use History Questionnaire to assess for lifetime cannabis use, and the Computerized Diagnostic Interview Schedule for Children, Fourth edition to assess the number of depression symptoms in the past year. Subtests from the Wechsler Memory Scale, Fourth Edition and the California Verbal Learning Test, Second Edition were used to assess episodic memory performance. The effect of the three-way interaction among cannabis use, depression symptoms, and sex did not have a significant impact on episodic memory performance. However, follow-up analyses revealed a significant effect of the two-way interaction of cannabis use and depression symptoms on episodic memory, such that associations between cannabis use and episodic memory were only significant at lower and average levels of depression symptoms. Contrary to our hypotheses, we found that as depression symptoms increased, the negative association between cannabis use and episodic memory diminished. Given the use of a predominantly subsyndromic sample, future studies should attempt to replicate findings among individuals with more severe depression.

The cerebellum is causally involved in episodic memory under aging

Episodic memory decline is a major signature of both normal and pathological aging. Many neural regions have been implicated in the processes subserving both episodic memory and typical aging decline. Here, we demonstrate that the cerebellum is causally involved episodic memory under aging. We show that a 12-day neurostimulation program delivered to the right cerebellum led to improvements in episodic memory performance under healthy aging that long outlast the stimulation period — healthy elderly individuals show episodic memory improvement both immediately after the intervention program and in a 4-month follow-up. These results demonstrate the causal relevance of the cerebellum in processes associated with long-term episodic memory, potentially highlighting its role in regulating and maintaining cognitive processing. Moreover, they point to the importance of non-pharmacological interventions that prevent or diminish cognitive decline in healthy aging.

Hippocampal Neuronal Activity Preceding Stimulus Predicts Later Memory Success.

Hippocampal neuronal activity at a time preceding stimulus onset affects episodic memory performance. We hypothesized that neuronal activity preceding an event supports successful memory formation; therefore, we explored whether a characterized encoding-associated brain activity, viz. the neuronal activity preceding a stimulus, predicts subsequent memory formation. To address this issue, we assessed the activity of single neurons recorded from the hippocampus in humans, while participants performed word memory tasks. Human hippocampal single-unit activity elicited by a fixation cue preceding words increased the firing rates (FRs) and predicted whether the words are recalled in a subsequent memory test; this indicated that successful memory formation in humans can be predicted by a preceding stimulus activity during encoding. However, the predictive effect of preceding stimulus activity did not occur during retrieval. These findings suggest that the preparative arrangement of brain activity before stimulus encoding improves subsequent memory performance.

White matter lesion load determines exercise-induced dopaminergic plasticity and working memory gains in aging

Age-related dopamine reductions have been suggested to contribute to maladaptive working memory (WM) function in older ages. One promising intervention approach is to increase physical activity, as this has been associated with plasticity of the striatal dopamine system and WM improvements, however with individual differences in efficacy. The present work focused on the impact of individual differences in white-matter lesion burden upon dopamine D2-like receptor (DRD2) availability and WM changes in response to a 6 months physical activity intervention. While the intervention altered striatal DRD2 availability and WM performance in individuals with no or only mild lesions (p < 0.05), no such effects were found in individuals with moderate-to-severe lesion severity (p > 0.05). Follow-up analyses revealed a similar pattern for processing speed, but not for episodic memory performance. Linear analyses further revealed that lesion volume (ml) at baseline was associated with reduced DRD2 availability (r = −0.41, p < 0.05), and level of DRD2 change (r = 0.40, p < 0.05). Taken together, this study underlines the necessity to consider cerebrovascular health in interventions with neurocognitive targets. Future work should assess whether these findings extend beyond measures of DRD2 availability and WM.

The role of metamemory and personality in episodic memory performance in older adults

This study newly investigated the joint contribution of metamemory and personality (traits and facets) in explaining episodic memory (EM) performance in typically aging older adults. Forty-eight participants (age range: 64–75 years) completed a self-paced word list (SPWL) recall task, a metamemory questionnaire assessing perceived control and potential improvement (PCPI) and self-efficacy and satisfaction (SESA) regarding one’s mental abilities (e.g., memory), and the Big-Five Questionnaire. Based on the SPWL encoding strategies reported, participants were then classified as effective (N = 20) or ineffective (N = 28) memory strategy users. Hierarchical regression analyses showed that a better SPWL performance was predicted by higher levels of PCPI, Scrupulousness and Dominance personality facets. Effective memory strategy users, then, showed higher SPWL performance and Dominance (Energy facet) than ineffective ones. These findings suggest that both specific metamemory processes and personality facets predict better EM performance in older adults. Moreover, personality dispositions relating to Dominance seem to characterize individuals adopting effective memory strategies to support EM performance. These results represent first evidence of the role of both metamemory and personality—facets—in explaining older adults’ EM performance, which should thus be considered when assessing or training EM in old age.

Lifetime Traumatic Brain Injury and Cognitive Domain Deficits in Late Life: The PROTECT-TBI Cohort Study.

Traumatic brain injury (TBI) causes cognitive impairment but it remains contested regarding which cognitive domains are most affected. Further, moderate-severe TBI is known to be deleterious, but studies of mild TBI (mTBI) show a greater mix of negative and positive findings. This study examines the longer-term cognitive effects of TBI severity and number of mTBIs in later life. We examined a subset (n = 15,764) of the PROTECT study, a cohort assessing risk factors for cognitive decline (ages between 50 and 90 years). Participants completed cognitive assessments annually for 4 years. Cognitive tests were grouped using a principal components analysis (PCA) into working memory, episodic memory, attention, processing speed, and executive function. Lifetime TBI severity and number were retrospectively recalled by participants using the Brain Injury Screening Questionnaire (BISQ). Linear mixed models (LMMs) examined the effect of severity of head injury (non-TBI head strike, mTBI, and moderate-severe TBI) and number of mTBI at baseline and over time. mTBI was considered as a continuous and categorical variable (groups: 0 mTBI, 1 mTBI, 2 mTBIs, 3 mTBIs, and 4+ mTBIs). Of the participants 5725 (36.3%) reported at least one mTBI and 510 (3.2%) at least one moderate-severe TBI, whereas 3711 (23.5%) had suffered at worst a non-TBI head strike and 5818 (32.9%) reported no head injuries. The participants had suffered their last reported head injury an average (standard deviation, SD) of 29.6 (20.0) years prior to the study. Regarding outcomes, there was no worsening in longitudinal cognitive trajectories over the study duration but at baseline there were significant cognitive deficits associated with TBI. At baseline, compared with those without head injury, individuals reporting at least one moderate-severe TBI had significantly poorer attention (B = -0.163, p < 0.001), executive scores (B = -0.151, p = 0.004), and processing speed (B = -0.075, p = 0.033). Those who had suffered at least a single mTBI also demonstrated significantly poorer attention scores at baseline compared with the no head injury group (B = -0.052, p = 0.001). Compared with those with no mTBI, those in the 3 mTBI group manifested poorer baseline executive function (B = -0.149, p = 0.025) and attention scores (B = -0.085, p = 0.015). At baseline, those who had suffered four or more mTBIs demonstrated poorer attention (B = -0.135, p < 0.001), processing speed (B = -0.072, p = 0.009), and working memory (B = -0.052, p = 0.036), compared with those reporting no mTBI. TBI is associated with fixed, dose, and severity-dependent cognitive deficits. The most sensitive cognitive domains are attention and executive function, with approximately double the effect compared with processing speed and working memory. Post-TBI cognitive rehabilitation should be targeted appropriately to domain-specific effects. Significant long-term cognitive deficits were associated with three or more lifetime mTBIs, a critical consideration when counseling individuals post-TBI about continuing high-risk activities.

Clinical performance of an antibody-free assay for plasma Aβ42/Aβ40 to detect early alterations of Alzheimer’s disease in individuals with subjective cognitive decline

BackgroundAccessible and cost-effective diagnostic tools are urgently needed to accurately quantify blood biomarkers to support early diagnosis of Alzheimer’s disease (AD). In this study, we investigated the ability of plasma amyloid-beta (Aβ)42/Aβ40 ratio measured by an antibody-free mass-spectrometric (MS) method, ABtest-MS, to detect early pathological changes of AD.MethodsThis cohort study included data from the baseline and 2-year follow-up visits from the Fundació ACE Healthy Brain Initiative (FACEHBI) study. Plasma Aβ42/Aβ40 was measured with ABtest-MS and compared to 18F-Florbetaben PET as the reference standard (cutoff for early amyloid deposition of 13.5 centiloids). Cross-validation was performed in an independent DPUK-Korean cohort. Additionally, associations of plasma Aβ42/Aβ40 with episodic memory performance and brain atrophy were assessed.ResultsThe FACEHBI cohort at baseline included 200 healthy individuals with subjective cognitive decline (SCD), of which 36 (18%) were Aβ-PET positive. Plasma Aβ42/Aβ40 levels were significantly lower in Aβ-PET positive individuals (median [interquartile range, IQR], 0.215 [0.203–0.236]) versus Aβ-PET negative subjects (median [IQR], 0.261 [0.244–0.279]) (P < .001). Plasma Aβ42/Aβ40 was significantly correlated with Aβ-PET levels (rho = −0.390; P < .001) and identified Aβ-PET status with an area under the receiver operating characteristic curve (AUC) of 0.87 (95% confidence interval [CI], 0.80–0.93). A cutoff for the Aβ42/Aβ40 ratio of 0.241 (maximum Youden index) yielded a sensitivity of 86.1% and a specificity of 80.5%. These findings were cross-validated in an independent DPUK-Korean cohort (AUC 0.86 [95% CI 0.77–0.95]). Lower plasma Aβ42/Aβ40 ratio was associated with worse episodic memory performance and increased brain atrophy. Plasma Aβ42/Aβ40 at baseline predicted clinical conversion to mild cognitive impairment and longitudinal changes in amyloid deposition and brain atrophy at 2-year follow-up.ConclusionsThis study suggests that plasma Aβ42/Aβ40, as determined by this MS-based assay, has potential value as an accurate and cost-effective tool to identify individuals in the earliest stages of AD, supporting its implementation in clinical trials, preventative strategies and clinical practice.

Verbal Episodic Memory Test

<p>The decline of episodic memory is one of the earliest cognitive markers of mild cognitive impairment and various types of dementia. Until today, however, there is no standardized Hun&shy;garian episodic memory test that takes into account the characteristics of the Hungarian language. The study presents the structure and standardized use of a new memory test (Verbal Episodic Memory Test, VEMT) as well as normative data in Hungary.&nbsp;</p>. <p>The VEMT is suitable for the comprehensive examination of verbal learning abilities in a broader sense, and more specifically, for the neuropsychological measurement of verbal list learning abilities. In the present study, we constructed a normative database consisting of data from 385 participants.</p>. <p>We showed that the VEMT is sensitive to demographic factors (e.g., age) which are linked to differences in episodic memory performance. Open access to the test is provided, and the normative scores are presented as well.&nbsp;</p>. <p>The indicators of the test are suitable for drawing a learning curve, for showing the interaction of new and previously learned information (interference effects), and for measuring differences between free recall and cued recall. Furthermore, the test scores are appropriate for distinguishing the effects of different types of memory encoding forms (phonological, semantic, and episodic), for measuring the ability to reconstruct the presentation of a sequence (memory order information), for detecting the rate of forgetting, for measuring recognition abilities, and for detecting hippocampus-related mnemonic pattern separation and completion functions.&nbsp;</p>.

Thalamic nuclei changes in early and late onset Alzheimer's disease.

Alzheimer's disease (AD) is the most common cause of dementia worldwide. Increasing evidence points to the thalamus as an important hub in the clinical symptomatology of the disease, with the 'limbic thalamus' been described as especially vulnerable. In this work, we examined thalamic atrophy in early-onset AD (EOAD) and late-onset AD (LOAD) compared to young and old healthy controls (YHC and OHC, respectively) using a recently developed cutting-edge thalamic nuclei segmentation method. A deep learning variant of Thalamus Optimized Multi Atlas Segmentation (THOMAS) was used to parcellate 11 thalamic nuclei per hemisphere from T1-weighted MRI in 88 biomarker-confirmed AD patients (49 EOAD and 39 LOAD) and 58 healthy controls (41 YHC and 17 OHC) with normal AD biomarkers. Nuclei volumes were compared among groups using MANCOVA. Further, Pearson's correlation coefficient was computed between thalamic nuclear volume and cortical-subcortical regions, CSF tau levels, and neuropsychological scores. The results showed widespread thalamic nuclei atrophy in EOAD and LOAD compared to their respective healthy control groups, with EOAD showing additional atrophy in the centromedian and ventral lateral posterior nuclei compared to YHC. In EOAD, increased thalamic nuclei atrophy was associated with posterior parietal atrophy and worse visuospatial abilities, while LOAD thalamic nuclei atrophy was preferentially associated with medial temporal atrophy and worse episodic memory and executive function. Our findings suggest that thalamic nuclei may be differentially affected in AD according to the age at symptoms onset, associated with specific cortical-subcortical regions, CSF total tau and cognition.

Grip strength, gait speed, and trajectories of cognitive function in community-dwelling older adults: A prospective study.

This study investigated whether grip strength and gait speed predict cognitive aging trajectories and examined potential sex-specific associations. Community-dwelling older adults (n=19,114) were followed for up to 7 years, with regular assessment of global function, episodic memory, psychomotor speed, and executive function. Group-based multi-trajectory modeling identified joint cognitive trajectories. Multinomial logistic regression examined the association of grip strength and gait speed at baseline with cognitive trajectories. High performers (14.3%, n=2298) and low performers (4.0%, n=642) were compared to the average performers (21.8%, n=3492). Grip strength and gait speed were positively associated with high performance and negatively with low performance (P-values<0.01). The association between grip strength and high performance was stronger in women (interaction P<0.001), while gait speed was a stronger predictor of low performance in men (interaction P<0.05). Grip strength and gait speed are associated with cognitive trajectories in older age, but with sex differences. There is inter-individual variability in late-life cognitive trajectories.Grip strength and gait speed predicted cognitive trajectories in older age.However, sex-specific associations were identified.In women, grip strength strongly predicted high, compared to average, trajectory.In men, gait speed was a stronger predictor of low cognitive performance trajectory.

Subjective cognitive decline is a better marker for future cognitive decline in females than in males

BackgroundThe identification of biomarkers for early detection of Alzheimer’s disease (AD) is critical to the development of therapies and interventions targeted at symptom management and tracking the pathophysiology of disease. The endorsement of subjective cognitive decline (SCD) has emerged as a potential indicator of early change in cognitive status that may be predictive of future impairment at a time when measurable declines in neuropsychological performance cannot be detected. While there are numerous findings revealing sex differences in the prevalence of AD, there is a paucity of research examining sex differences in SCD. Therefore, the goal of this project was to determine if the relationship between the endorsement of SCD and future cognitive changes differ as a function of biological sex.MethodsA sample of 3019 male and female healthy older adults (2188 without SCD, 831 with SCD), with a mean follow-up time of 5.7 years, were included from the Rush Alzheimer’s Disease Center Research Sharing Hub. Linear regressions were performed to determine group differences in baseline cognitive scores, while linear mixed-effects models were completed to determine group differences in the rate of cognitive change over time.ResultsIndividuals endorsing SCD had significantly lower baseline cognitive scores and increased rates of decline in all cognitive domains compared to those without SCD. Males exhibited significantly lower scores in baseline performance in global cognition, episodic memory, and perceptual speed regardless of SCD classification. Females with SCD were found to decline at significantly faster rates than both males with SCD and males and females without SCD in all cognitive domains over a maximum 15-year follow-up period.ConclusionsSCD is related to lower baseline cognitive performance and faster cognitive decline compared to those who do not endorse SCD. Females with SCD have the fastest rate of decline suggesting that SCD may be more predictive of future decline in females than in males. Targeted assessments of SCD may allow for the identification of individuals for inclusion in intervention trials, and other research studies, aiming to attenuate casual disease processes, which may ultimately aid in the mitigation of sex disparities in AD.

LONGITUDINAL ASSOCIATIONS BETWEEN PERSONAL GROWTH AND COGNITIVE FUNCTIONING IN ADULTHOOD

Abstract 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. 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 structural equation model was analyzed to assess cross-lagged 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. The results indicated that 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. 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.

ARE CAREGIVERS HEALTHIER?: ASSESSING CAREGIVERS' EPISODIC MEMORY IN A MATCHED AND UNMATCHED SAMPLE

Abstract Recent findings using an advanced methodological technique of propensity matching have found that caregivers may have better cognitive health compared to non-caregivers. However, there are limited studies assessing how personality and other psychosocial variables may affect the relationship between caregiver status and cognition. Utilizing the healthy caregiver hypothesis (HCH), the current study examined the association between caregiving and episodic memory in a matched (N= 1,246) and unmatched (N=3,112) sample of caregivers from the 2016 wave of the Health and Retirement Study. The interaction between caregiving status and personality was also examined. Unadjusted models showed no difference between caregiver status and episodic memory in the samples; however, depression was significantly (p=&amp;lt;.0001) related to cognition in the unmatched sample. In adjusted models for the unmatched sample, conscientiousness (p=0.043), pessimism (p=0.006), and feeling constrained (p=0.028) were found to be significantly associated with episodic memory. In the matched adjusted models, conscientiousness was no longer a significant predictor, but number of chronic conditions was significantly related to episodic memory (p=0.001). The interaction between caregiving and extraversion also approached significance (p=0.076). Findings suggest extraverted caregivers may have better episodic memory performance. These findings highlight the importance of implementing propensity matching in caregiving research. Future research is needed to examine the relationship between coping style and personality specific domains in relation to the HCH.

CHANGE IN EPISODIC MEMORY AND EXECUTIVE FUNCTIONING PREDICTS MORTALITY RISK

Abstract The current study explored whether the Brief Test of Adult Cognition via Telephone (BTACT) assessment could be used to predict longevity in a national sample of adults from the Midlife Development in the United States (MIDUS) study. Specifically, we examined whether 9-year changes in episodic memory (EM) and executive functioning (EF) predicted all-cause mortality risk (2004-2018). The sample included 2,643 participants (MAge=45.87; 92.23% white; 107 deceased) who completed the BTACT twice: between 2004-06 and between 2013-2017. Using change scores, decreases in EM (HR= 1.45 [1.09-1.93], p=.01) and EF (HR=1.585 [1.17-2.14], p&amp;lt;.001) increased the hazard of dying (controlling for age, gender, race, education, and self-rated health). Results suggest the BTACT is sensitive enough to detect health-consequential decreases in EM/EF. Future research should consider the BTACT as a viable assessment tool for older adults who may not have easy access to cognitive screenings.

KEY PREDICTORS OF COGNITIVE AGING

Abstract Understanding who will experience cognitive dysfunction and dementia is as important as identifying methods to combat such deterioration. This symposium seeks to highlight new advances in understanding cognitive deterioration and promote resilience in adulthood. Odd and colleagues utilized a national sample (2,643 adults aged 34-85) to show that 9-year decreases in executive function and episodic memory predicted increased risk of dying. Use of a brief cognitive assessment administered via telephone was unique – a method that may assist clinicians administering cognitive screenings to older adults in isolated areas. Graham and colleagues utilized a daily diary approach in 116 older adults (aged 60-90) to show that greater daily fluctuations in mindfulness were associated with higher episodic memory and executive functioning. Further, mediational evidence suggested that on days when mindfulness was greater, individuals perceived a younger subjective age. Willroth and colleagues provide evidence that higher scores on eudaimonic well-being in older adults (n=349) predicted greater cognitive resilience. Specifically, even though some participants had neuropathological burden (e.g., increased beta-amyloid, neurofibrillary tangles), they did not exhibit pronounced cognitive declines. Using data from 14 longitudinal studies, Yoneda and colleagues examined the impact of physical activity on cognitive impairment and death. Multi-state survival analyses demonstrated engagement in more physical activity reduced risk of cognitive impairment and death. This symposium suggests that examining changes in cognition, incorporating subjective and objective indices of cognitive impairment, utilizing long-term longitudinal and daily diary designs, and testing key modifiable behaviors is crucial to understanding and promoting optimal cognitive functioning in adulthood.

DUAL-TASK TRAINING FOR IMPROVING COGNITIVE-MOTOR INTERFERENCE

Abstract Dr. Bhatt will discuss the differences in types of cognitive motor interference patterns experienced for different tasks (gaitand volitional versus reactive balance) in cognitively intact versus people with mild cognitive impairment. She will discuss the effectiveness of dual-task training and exergaming on gait, volitional and reactive balance control in older adults with mild cognitive impairment. After 4 weeks of such training, the results showed beneficial effects on improving volitional based performance when performed with a cognitive task (i.e., spatial memory and executive function) and had significant improvement in NIH toolbox (cognitive- increased working memory, episodic memory and executive function, and motor-increased gait speed). However, its positive effects on dual task reactive balance control were limited. Additionally, the speaker will go on to discuss the associations of balance control deficits in mild cognitive impairment with neural correlates (structural and functional brain integrity) to understand the attributing factors to increased fall risk in people with mild cognitive impairment.

THE ROLE OF SLEEP DISTURBANCE IN COGNITIVE OUTCOMES AMONG LONELY ADULTS IN THE HEALTH AND RETIREMENT STUDY

Abstract Both sleep disturbance and loneliness have been linked to poorer cognitive performance and increased risk of dementia in older adults. Loneliness is believed to influence cognitive functioning directly and indirectly through the HPA axis dysfunction, which increases systemic inflammation through endocrine, immune system, and genetic pathways which produce a range of negative effects on brain tissue. Higher levels of HPA axis activity associated with lonely feelings may lead to poorer sleep quality, which decreases beta-amyloid and tau clearance, as well as memory consolidation, which may further disrupt sleep through alterations in brain tissue. Despite the growing body of research, little is known about how sleep disturbance and loneliness, both modifiable risk factors, interact to effect cognition and dementia risk over time. Secondary analysis of the 2006, 2010, 2014, and 2018 waves of the Health and Retirement Study was completed using data from 1,092 participants (mean age: 66.24; SE: .1366). Mixed effects regression modeling was used to evaluate the role of sleep disturbance in the relation between loneliness (R-UCLA loneliness scale, 11 item) and four cognitive performance measures: Immediate and Delayed Word Recall, Serial 7s, and Backward Count, and cognitive status category (cognitively normal, cognitively impaired, and dementia) across a 12-year period. Sleep disturbance moderated the relation between loneliness and Immediate Word Recall (p=.048) and Serial 7s (p=.032) outcomes even after controlling for demographic covariates and depression. Findings suggest that sleep disturbance may exacerbate the negative physiological effects of loneliness on episodic memory and executive functioning in older adults.

Metamemory Mediates the Effects of Age on Episodic and Working Memory across the Adult Lifespan

ABSTRACT Background Previous studies have examined the direct relationship between metamemory and memory performance in young and older adults, but the results of these studies have been inconsistent. Therefore, we examined whether metamemory mediates the effects of age on memory performance. Methods We examined episodic memory and working memory through computerized tasks performed by a lifespan sample of 1554 healthy adults. Seven metamemory traits were measured with the Metamemory in Adulthood (MIA) questionnaire. Separate structural equation modeling analyses were conducted to investigate potential metamemory mediators that intervened between age and the accuracy and speed of accessing information from episodic and working memory. Results The use of internal or external strategies mediated the effects of age on episodic memory and spatial working memory performance. The perception of one’s own memory capacity and the experience of anxiety when using memory functions mediated the effects of age on working memory performance in both domains. Conclusions Metamemory traits have the power to strengthen or weaken the course of episodic and working memory decline throughout adulthood.

Effects of Mindfulness Training and Exercise on Cognitive Function in Older Adults

Episodic memory and executive function are essential aspects of cognitive functioning that decline with aging. This decline may be ameliorable with lifestyle interventions. To determine whether mindfulness-based stress reduction (MBSR), exercise, or a combination of both improve cognitive function in older adults. This 2 × 2 factorial randomized clinical trial was conducted at 2 US sites (Washington University in St Louis and University of California, San Diego). A total of 585 older adults (aged 65-84 y) with subjective cognitive concerns, but not dementia, were randomized (enrollment from November 19, 2015, to January 23, 2019; final follow-up on March 16, 2020). Participants were randomized to undergo the following interventions: MBSR with a target of 60 minutes daily of meditation (n = 150); exercise with aerobic, strength, and functional components with a target of at least 300 minutes weekly (n = 138); combined MBSR and exercise (n = 144); or a health education control group (n = 153). Interventions lasted 18 months and consisted of group-based classes and home practice. The 2 primary outcomes were composites of episodic memory and executive function (standardized to a mean [SD] of 0 [1]; higher composite scores indicate better cognitive performance) from neuropsychological testing; the primary end point was 6 months and the secondary end point was 18 months. There were 5 reported secondary outcomes: hippocampal volume and dorsolateral prefrontal cortex thickness and surface area from structural magnetic resonance imaging and functional cognitive capacity and self-reported cognitive concerns. Among 585 randomized participants (mean age, 71.5 years; 424 [72.5%] women), 568 (97.1%) completed 6 months in the trial and 475 (81.2%) completed 18 months. At 6 months, there was no significant effect of mindfulness training or exercise on episodic memory (MBSR vs no MBSR: 0.44 vs 0.48; mean difference, -0.04 points [95% CI, -0.15 to 0.07]; P = .50; exercise vs no exercise: 0.49 vs 0.42; difference, 0.07 [95% CI, -0.04 to 0.17]; P = .23) or executive function (MBSR vs no MBSR: 0.39 vs 0.31; mean difference, 0.08 points [95% CI, -0.02 to 0.19]; P = .12; exercise vs no exercise: 0.39 vs 0.32; difference, 0.07 [95% CI, -0.03 to 0.18]; P = .17) and there were no intervention effects at the secondary end point of 18 months. There was no significant interaction between mindfulness training and exercise (P = .93 for memory and P = .29 for executive function) at 6 months. Of the 5 prespecified secondary outcomes, none showed a significant improvement with either intervention compared with those not receiving the intervention. Among older adults with subjective cognitive concerns, mindfulness training, exercise, or both did not result in significant differences in improvement in episodic memory or executive function at 6 months. The findings do not support the use of these interventions for improving cognition in older adults with subjective cognitive concerns. ClinicalTrials.gov Identifier: NCT02665481.