Despite empirical evidence linking loneliness and social isolation to cognitive decline (CD) in later life, the underlying physiological and psychobehavioral mechanisms remain unclear. We conducted a systematic review to synthesize relevant evidence. Studies examining psychobehavioral pathways required mediation analyses, whereas studies on physiological pathways were included when mediation was examined or when outcomes are dementia-related neuropathological changes. Thirty-eight articles were included. Evidence pointed to multiple physiological mechanisms, including Alzheimer's disease pathology, brain structural differences, inflammation, cardiovascular risks, neurotrophic factors, hypothalamic-pituitary-adrenal (HPA) -axis function, gene expression, and general health, although findings were mixed. Psychobehavioral pathways, including depressive symptoms, neuroticism, lower sense of control, sleep disturbance, and lower engagement in social or leisure activities, mediated the association. This review identified mechanistic targets that may be leveraged in non-pharmacological interventions. Future intervention programs aimed at reducing social isolation and loneliness to delay CD could investigate whether they impact physiological and psychobehavioral pathways summarized here.

OBJECTIVES:This paper examined how momentary negative affect (NA) and positive affect (PA) are linked to ambulatory cognitive performance and whether these associations vary by age. Although prior research has identified between-person associations linking affect and cognitive performance, few ecological momentary assessment studies have investigated within-person relationships across adulthood. METHODS:Data were drawn from the Effects of Stress on Cognitive Aging, Physiology, and Emotion (ESCAPE) study. Participants were 260 racially and economically diverse adults aged 25-65 (Mage = 46.5) who completed five daily assessments over 14 days. At each assessment, participants reported their current affect and completed brief, standardized cognitive tasks via smartphone. Multilevel models examined within-person associations between NA, PA and ambulatory cognitive performance (processing speed, working memory, spatial memory) and tested age as a moderator. RESULTS:Across all ages, moments of heightened NA (compared to individuals' averages) were related to worse working memory (γNA = -0.0004, SE = 0.0002, p = .02). Moments of heightened NA were related to decreases in processing speed (γNA = -0.0001, SE = 0.0000, p = .02) but only among adults around the sample mean age (46 years) and older. In contrast, moments of heightened PA were associated with decreases in working memory (γPA = -0.0003, SE = 0.0002, p = .04) only among adults under the sample mean age. No significant associations were observed between momentary affect and spatial memory. CONCLUSION:These results indicate that within-person associations between affect and cognition in daily life vary as a function of age-related contextual and behavioral factors. These findings suggest potential clinical implications for cognition, particularly during periods of elevated NA in later midlife.

Loneliness is a worldwide concern with significant health implications that may be a significant risk factor for Alzheimer’s disease and related dementias. In light of the importance of detecting early cognitive changes and risk factors influencing cognitive health, this study examined whether chronic loneliness predicted cognitive changes among young and middle-aged adults. This study utilizes data from a longitudinal measurement burst study spanning over two years, comprising three waves of data collection. A systematically recruited young to mid-life adult sample (25- 65 years) included 172 racially and economically diverse participants who provided information about loneliness for at least two consecutive waves. Chronic loneliness was defined based on the validated multi-item PROMIS Social Isolation scale. We assessed working memory, processing speed, and spatial memory in a measurement burst design using mobile cognitive assessments. Multilevel growth models were conducted to examine whether chronic loneliness was associated with changes in cognitive performance during the study period of up to two years. Results revealed that chronic loneliness was not associated with baseline performance of working memory, processing speed, spatial memory or global cognitive performance, but chronic loneliness was associated with differential cognitive trajectories, specifically a lack of retest related improvement. There were no significant changes in cognitive performance for the chronic loneliness group across waves, whereas significant improvements were observed in those who were not chronically lonely. This study offers insights into the impact of chronic loneliness on cognitive changes in young and middle-aged adults, revealing that chronically lonely individuals did not exhibit the practice-related improvements that are commonly observed in longitudinal studies. Findings suggest the potential significance of identifying and addressing chronic loneliness promptly to prevent potential cognitive consequences of chronic loneliness.

Loneliness is linked to a wide range of negative outcomes, including worse emotional well-being. Although prior research has demonstrated the relationship between loneliness and typical levels of negative and positive emotions, the degree to which loneliness is associated with emotional instability, a potential indicator of unhealthy patterns of emotional experiences, is unknown. We evaluated whether individual differences in loneliness were related to instability across days in positive emotions (PE) and negative emotions (NE) in daily life. A diverse community sample of 252 adults (age 25-65) completed a baseline assessment of loneliness followed by 14 days of ecological momentary assessments, during which participants reported PE and NE five times each day. Loneliness was significantly associated with greater instability in both PE and NE, after adjusting for demographic characteristics, objective social isolation, and person-mean emotion levels. Notably, the association with PE instability remained significant even after controlling for depressive symptoms, whereas the association with NE instability was attenuated and no longer significant. These findings suggest that loneliness is characterised not only by differences in average emotional states but also by greater emotional variability, particularly in PE, which may be a key feature linking loneliness to broader health and well-being outcomes.

Despite extensive evidence linking loneliness and social isolation to cognitive decline in later life, the underlying pathophysiological and psychosocial mechanisms remain unclear. This systematic review synthesizes existing research to clarify these pathways. A comprehensive search was conducted across PubMed, Web of Science, EMBASE, and PsycINFO until October 2024. Using Covidence for literature management, we included peer-reviewed studies in English involving human participants aged 50+. Studies examining psychosocial pathways required mediation analyses, whereas studies on physiological pathways were included if outcomes were related to dementia pathology. From 4,314 unique articles, 40 met the inclusion criteria. Identified pathophysiological mechanisms included amyloid-beta and tau levels, grey matter atrophies, white matter hyperintensities, dementia-related gene expression, reduced brain-derived neurotrophic factor (BDNF), hypothalamic-pituitary-adrenal (HPA) axis dysregulation, and impaired cerebral blood flow. Psychosocial mediators encompassed depression, anxiety, sleep disturbances, physical inactivity, personality traits, and diminished sense of control. The presentation will contrast the unique pathways for loneliness and social isolation. Evidence suggests loneliness and social isolation are linked to decreased resiliency to neuropathological changes and to behavioral and psychological factors that accelerate cognitive decline. However, existing research relies heavily on self-report measures and does not account for potential confounders like pre-existing health conditions, which limits causal inference. By integrating evidence across disciplines, our findings underscore the multifaceted impact of social disconnection on cognitive health. Future research should prioritize rigorous longitudinal designs, including multi-modal biomarkers, both subjective and objective psychosocial measures, and potential confounders in analyses. Such work would inform targeted interventions that promote cognitive resilience.

Loneliness is linked with risk for cognitive decline and dementia among older adults, but the degree to which it predicts future risk is unclear. To investigate if loneliness acts as a predictor of cognitive decline, this study employed a measurement burst design using data from the Einstein Aging Study, where loneliness and cognition were repeatedly assessed daily, for several days, across several years. In this type of data, a major challenge to detecting subtle cognitive changes is the presence of retest/practice effects. We employed a novel process modeling approach (Bayesian Double Exponential Model; BDEM) to distinguish retest learning effects from genuine longitudinal cognitive changes. Participants (n = 313; English-speaking, community-residing adults aged ≥70) underwent up to six waves of annual assessments. Each wave included a 16-day ambulatory ecological momentary assessment (EMA) burst on mobile phones. Ambulatory assessments consisted of self-report (including a question about feeling lonely now) and cognitive tests, conducted multiple times daily. This study analyzed the spatial working memory task. Cognitive parameters capturing retest learning rate, peak performance (disentangled from retest learning) and long-term changes in peak performance were estimated simultaneously using the BDEM. Regression analyses examined associations between mean and standard deviation (SD) of EMA loneliness at baseline and cognitive markers, controlling for demographics and mild cognitive impairment (MCI) status at baseline. A higher mean and a higher variability (SD) of EMA loneliness at baseline predicted higher baseline asymptotic (peak) performance, suggesting worse peak cognitive performance at baseline. However, neither mean level nor variability of EMA loneliness at baseline predicted changes in peak performance after baseline. Notably, a higher variability of EMA loneliness was also associated with slower learning rates from repeated testing across bursts. This study reveals that the level and variability of loneliness in daily life, measured in near-real time, predict concurrent peak performance and long-term learning rates in working memory among older adults. Results, particularly regarding loneliness variability, suggest that the experience of loneliness has implications for long-term learning rates. Not only the mean level of loneliness, but also variations in loneliness, have separate predictive value for cognitive performance over time.

Mental health and cognitive performance fluctuate with daily experiences, yet most research relies on retrospective reports that do not capture real-time variations. Ecological momentary assessment (EMA) enables examination of how contextual experiences unfold in everyday life. This symposium showcases studies using EMA to investigate how psychological and cognitive processes in daily life influence cognitive experiences in aging populations and how they represent potential entry points for intervention. First, Dr. Compernolle will describe social and physical contexts that contribute to fluctuations in loneliness—an important indicator of social and mental well-being—using findings from the Chicago Health and Activity Space in Real Time study. Next, Drs. Kang and Felt will highlight the dynamic relationship between loneliness and cognitive performance in daily life in an Einstein Aging Study cohort. Kang will discuss the reciprocal association between loneliness and daily memory lapses, demonstrating how loneliness both predicts and results from memory lapses. Felt will explore bidirectional links between loneliness and objective cognitive performance, showing that higher cognitive performance predicts lower subsequent loneliness, whereas loneliness is associated with slower processing speed. Finally, Dr. Sutin will describe how fluctuations in momentary purpose in life link with cognitive performance, revealing that while greater purpose is linked to better cognitive performance, it may also temporarily tax attentional resources, leading to increased memory lapses. Together, these presentations will highlight how momentary psychological experiences—including loneliness and purpose in life—shape cognitive performance and vice versa, emphasizing the importance of real-time assessments in understanding and promoting cognitive and emotional well-being in later life.

Loneliness affects 24-33% of older adults and has been associated with a 26% increased risk for developing Alzheimer’s Disease and related dementias (ADRDs). Given that ADRDs have a long preclinical period, loneliness may arise in response to earlier cognitive changes and act as a preclinical indicator. The purpose of this study was to investigate bidirectional associations between loneliness and cognitive performance in older adults. Data comes from a burst of the Einstein Aging Study, a community sample of 318 adults over the age of 70 from Bronx, NY who were dementia free at baseline. Participants completed 5 ecological momentary assessments (EMAs) per day for 14 consecutive days. Participants self-reported how lonely they felt and completed 3 brief (∼45 seconds per task) cognitive tasks at each EMA (Grid Memory, Color Shapes, and Symbol Search). We used dynamic structural equation modeling (DSEM) to test the cross-lagged relations between loneliness and cognitive performance on the three tasks (∼every 3-4 hours). Results indicated that higher cognitive performance at one EMA was associated with lower levels of loneliness on the following EMA for the proportion of shapes correctly identified in the Color Shape task. There was also some evidence that higher levels of loneliness were associated with slower reaction time on the Symbol Search task. Further, higher levels of loneliness at one EMA were associated with slower performance on the Color Shape task. These results will be discussed in the context of pre-clinical mechanisms and additional results on multiple burst data will be presented.

Although loneliness is a known risk factor for cognitive decline, the degree to which it predicts subjective cognitive functioning—such as daily memory lapses—is unclear. Moreover, memory difficulties themselves may contribute to feelings of loneliness by disrupting social interactions and diminishing confidence in cognitive abilities. This study utilized ecological momentary assessment (EMA) data to examine the bidirectional daily associations between loneliness and self-reported prospective (PM) and retrospective memory (RM) lapses. A sample of 263 older adults (mean age = 77 years, 67% women, 43% Black, 31% MCI) completed 14 days of EMA, reporting momentary loneliness (5×/day) and daily memory lapses each evening. Multilevel models tested the effects of loneliness on same-day and next-day memory lapses and vice versa, controlling for study day, age, gender, education, MCI status, marital status, living arrangement, and prior-day outcomes. On days when participants felt lonelier than usual, they were more likely to forget meetings (OR = 1.07, p=.052), although this effect was marginally significant; moreover, forgetting meetings predicted higher loneliness the next day (b = 4.2, p=.003). Further, greater irritation from PM lapses was associated with higher loneliness on the same (b=.03, p=.020) and next day (b=.03, p=.04). Higher loneliness was also associated with forgetting important information (OR = 1.03, p=.049) on the same day and misplacing items the next day (OR = 1.03, p=.010). Findings highlight a potentially bidirectional relationship, suggesting that loneliness contributes to daily cognitive difficulties, which, in turn, may reinforce loneliness. Addressing memory lapses as well as loneliness may help support cognitive and emotional well-being in aging populations.

Previous work suggests that loneliness leads to greater affective responsivity, which is generally related to poorer emotional well-being and health. The aim of the present research was to investigate whether individual differences in loneliness moderated affective responses to everyday uplifts. Using ecological momentary assessment (EMA), participants (N = 240; aged 20-65 years) reported recent uplifting experiences, and their current positive and negative affective states 5x/day for 14 days. Trait loneliness was measured in the baseline survey prior to the beginning of the EMAs. Multilevel regression analyses revealed that those with higher loneliness experienced greater immediate decreases in negative affect (NA) and increases in positive affect (PA) on occasions when they reported a recent uplift, compared to those with lower loneliness. However, loneliness did not moderate lagged effects of uplifts on either NA or PA, indicating that the emotional benefits of uplifting events for lonelier individuals did not persist to the next assessment. These findings suggest that although uplifting events significantly boosted PA and reduced NA among lonely individuals in the short-term, these effects did not have a lasting impact. The immediate affective benefits of uplifts for lonelier individuals tend to be fleeting and may be insufficient to maintain mood stability, possibly leading to additional emotional strain.

Objectives Despite extensive efforts to study individual differences in loneliness and neurocognitive health, little is known about how within-person changes in state loneliness relate to cognitive performance. This study addressed this gap by examining the association between within-person variation in state loneliness and cognitive performance assessed objectively in daily life.Methods Participants were 313 community-dwelling older adults (70-90 years) who reported momentary feelings of loneliness and completed smartphone-based cognitive tests 5 times daily for 14 consecutive days. Mobile cognitive tests assess visual associative memory, processing speed, and spatial memory.Results At the day level, average state loneliness levels were negatively related to cognitive performance on the same day and subsequent day. Consistent with the day-level analysis, momentary assessments of increased loneliness were consistently linked to worse cognitive performance on concurrent assessments. However, moments characterized by lower cognitive performance predicted higher levels of loneliness 3-4 hr later (next occasion), but not vice versa.Discussion The findings suggest a prospective association between loneliness and cognitive performance, with higher daily loneliness negatively associated with cognitive performance on the same day and predicting worse performance the following day. Notably, within a single day, lower cognitive performance at a given moment predicted elevated loneliness later in the day. This highlights a complex, reciprocal relationship-loneliness predicting and being predicted by cognitive performance depending on timescale.

OBJECTIVES:Loneliness is associated with maladaptive cognitions, yet little is known about the association between loneliness and intrusive thinking during older adulthood. Links between loneliness and intrusive thoughts may be particularly strong among individuals with mild cognitive impairment (MCI), who may have greater difficulty regulating emotion and intrusive thoughts. In contrast, having close relationships (e.g. being married) may serve as a protective factor as marital status is associated with better overall well-being. METHOD:Participants were 316 older adults (recruited from the Bronx, NY, as part of a larger study) without dementia at study intake (40% Black; 13% Hispanic, Mage = 77.45 years, 67% women) who completed ecological momentary assessments five times daily for 14 consecutive days (13,957 EMAs total). Multilevel modeling was used to examine the association between momentary loneliness and intrusive thoughts and whether MCI and marital status interacted to moderate this association. RESULTS:There was a significant three-way interaction (β = -0.17, p < 0.05), such that lagged momentary loneliness was positively associated with intrusive thoughts (3-4 h later) for those with MCI who were not married. CONCLUSION:Findings suggest that among older adults with MCI, being married may be a protective factor and being unmarried may be a risk factor for experiencing loneliness and subsequent intrusive thoughts.

Abstract Loneliness has been linked to objective cognitive decline and dementia risk; however, less is known about how loneliness relates to subjective cognition. Assessing daily subjective cognition related to prospective memory (i.e., for future events; PM) and retrospective memory (i.e., for past information; RM) may be particularly useful in identifying associations with daily emotional and cognitive health. The current research examined associations between loneliness and self-reported PM and RM lapses among 311 older adults (mean age=77.45 years, 40% Black, 13% Hispanic, 67% women) who completed 14 consecutive days of ecological momentary assessment that included self-reports of momentary loneliness (5x/day) as well as evening self-reports of memory lapses that occurred that day. Separate multilevel models were estimated to assess daily associations between loneliness and number of PM or RM lapses, and the amount of disruption and irritation associated with these lapses. All models controlled for age, gender, years of education, MCI status, and depressive symptoms. Days when loneliness was higher than typical were significantly associated with a higher number of PM lapses (b=0.011, p<.001), and more disruption to daily activities (b=0.113, p <.001) and irritation (b=0.036, p=.002) associated with experiencing PM lapses. Daily loneliness was not associated with the number of RM lapses, but was significantly linked with more disruption to daily activities (b=0.131, p<.001) and irritation associated with RM lapses (b=0.103, p<.001). Findings suggest that loneliness may uniquely impact daily PM and perceived disruption from RM issues, which has important implications for cognitive health and maintaining independence in late life.

BACKGROUND:Loneliness has been highlighted as a risk factor for dementia. However, the nature of the relationship between loneliness and cognitive function prior to onset of dementia is unclear.OBJECTIVE:The aim of this systematic review and meta-analysis was to examine the relationship between loneliness and cognitive function in samples screened for dementia at study commencement.METHODS:Five electronic databases (PubMed, PsycNET, Web of Science, EBSCOhost, Scopus) were searched from inception to August 31, 2021. A narrative review and random-effects meta-analysis were conducted on studies meeting search criteria. PROSPERO registration number: CRD42020155539.RESULTS:The sixteen studies that met inclusion criteria involved 30,267 individuals, with mean age ranging from 63.0 to 84.9 years. Studies varied in dementia screening criteria, measurement of loneliness and cognitive function, and statistical modeling approach. The narrative review indicated that loneliness was associated with poorer global cognition, episodic memory, working memory, visuospatial function, processing speed, and semantic verbal fluency. Results of the meta-analysis indicated that loneliness was negatively associated with global cognitive function (overall r = -0.08; 95% CI = -0.14, -0.02; n = 6). Due to lack of sufficient data and heterogeneity between studies, we were unable to explore associations with other cognitive domains or longitudinal associations.CONCLUSION:Loneliness is associated with subtle impairment across multiple cognitive domains in older adults who were screened for dementia. Better characterization of this relationship will provide important information about how loneliness contributes to the clinical and pathological sequalae of AD and be informative for risk reduction and early detection strategies.

Loneliness influences how people experience and respond to stressors, which may account for its role as a risk factor for morbidity and mortality. The present study was motivated by emerging evidence that affective responses to minor daily events have long-term implications for health and well-being. Specifically, we evaluated how individual differences in loneliness relate to the frequency of everyday stressors and stressor-related negative emotions. A diverse community sample of 255 adults (age 25-65 years) completed ecological momentary assessments (EMA), during which they reported recent stressors and current negative affect (NA) five times a day for 14 days. Multilevel logistic analyses indicated that there was a quadratic association between loneliness and likelihood of reporting stressors, controlling for demographics, social isolation, depressive symptoms, and context (current activities, current location). Multilevel regression indicated that loneliness was unrelated to the concurrent effect of stressors on NA but significantly larger lagged stressor effects were observed among individuals in the low and high ranges of loneliness. These findings suggest that individuals with high levels of loneliness are more likely to experience everyday stressors and have prolonged emotional responses following stressors.

Abstract Disturbed sleep is a common problem and can have profound effects on older adults. Social relationships are known to be associated with quantity and quality of sleep. To extend prior research, we examined the associations of daily social interactions and sleep, using objective sleep measures and an ecological momentary assessments (EMA) approach. Participants in the Einstein Aging Study (n=285, Mage=77, range=70-90, 68% women, 46% White, 40% Black) reported their recent social interactions and physical contact four times a day for 16 days via EMA on mobile phones. Objective sleep measures (sleep timing, night sleep time, wake after sleep onset (WASO), sleep maintenance efficiency) were calculated from concurrent wrist actigraphy. Multilevel models controlled for demographics, living arrangement, Instrumental Activities of Daily Living, sleep-disordered breathing, and hypoxemia. Results showed that, on days when older adults had more day-time social interactions than their average, they had earlier sleep timing, shorter night sleep time, and less WASO, but no differences in sleep efficiency. On days when older adults had more physical contact than their average, they had earlier sleep timing and shorter night sleep time but no differences in WASO or sleep efficiency. These micro-longitudinal analyses among older adults suggest that daily social interactions are related to subsequent earlier sleep timing and shorter sleep at night, and can be beneficial for sleep quality. Physical contact seemed to be only associated with the timing and quantity of sleep but not sleep quality. Potential benefits of using an EMA approach in sleep research will be discussed.

Abstract Poor sleep quality is a common problem and has profound physical and mental effects on older adults. Loneliness, another common and harmful condition for older adults, is associated with heightened levels of vigilance and feeling unsafe, which may contribute to poor sleep. Although some studies show that trait loneliness is related to compromised sleep, there are few studies examining whether and how day-to-day variations in loneliness relate to sleep quality. The current study aimed to examine within- and between-person associations of loneliness and daily self-rated sleep quality using ecological momentary assessment (EMA) approach. Community-dwelling participants (n=317, Mage=77 (range=70–90), 56% white) reported loneliness and self-rated sleep quality during a 14-day EMA study via mobile phones. Trait loneliness was measured once prior to EMA. Unexpectedly, multilevel modeling showed that the amount of loneliness experienced on a given day did not predict sleep quality, however lower levels of prior night sleep quality predicted elevated levels of loneliness (p < .01). Regarding the between-person association, individual differences in trait loneliness were not related to sleep quality, but differences in average levels of EMA loneliness were related to sleep quality, such that people who felt higher levels of loneliness on average during the 14 days reported worse quality of sleep during that time period than others (p < .0001). These results suggest that worse sleep quality may be a factor that increases loneliness, and may not be a consequence of loneliness. Potential benefits of using EMA loneliness in research of daily sleep quality in older adults will be discussed.

Background Individuals’ emotional responses to stressors in everyday life are associated with long-term physical and mental health. Among many possible risk factors, the stressor-related emotional responses may play an important role in future development of depressive symptoms. Purpose The current study examined how individuals’ positive and negative emotional responses to everyday stressors predicted their subsequent changes in depressive symptoms over 18 months. Methods Using an ecological momentary assessment approach, participants (n = 176) reported stressor exposure, positive affect (PA), and negative affect (NA) five times a day for 1 week (n = 5,483 observations) and provided longitudinal reports of depressive symptoms over the subsequent 18 months. A multivariate multilevel latent growth curve model was used to directly link the fluctuations in emotions in response to momentary stressors in everyday life with the long-term trajectory of depressive symptoms. Results Adults who demonstrated a greater difference in stressor-related PA (i.e., relatively lower PA on stressor vs. nonstressor moments) reported larger increases in depressive symptoms over 18 months. Those with greater NA responses to everyday stressors (i.e., relatively higher NA on stressor vs. nonstressor moments), however, did not exhibit differential long-term changes in depressive symptoms. Conclusions Adults showed a pattern consistent with both PA and NA responses to stressors in everyday life, but only the stressor-related changes in PA (but not in NA) predicted the growth of depressive symptoms over time. These findings highlight the important—but often overlooked—role of positive emotional responses to everyday stressors in long-term mental health.