Improved intraindividual variability in cognitive performance following cognitive and exercise training in older adults.

OBJECTIVE: Increased intraindividual variability (IIV) of cognitive performance is a marker of cognitive decline in older adults. Whether computerized cognitive training (CCT) and aerobic exercise counteracts cognitive decline by reducing IIV is unknown. We investigated the effects of CCT with or without aerobic exercise on IIV in older adults. METHODS: This was a secondary analysis of an 8-week randomized controlled trial. Older adults (aged 65-85 years) were randomized to CCT alone (n = 41), CCT with aerobic exercise (n = 41), or an active control group (n = 42). The CCT group trained using the Fit Brains® platform 3×/week for 1 hr (plus 3×/week of home-based training). The CCT with aerobic exercise group received 15 min of walking plus 45 min of Fit Brains® 3×/week (plus 3×/week of home-based training). The control group received sham exercise and cognitive training (3×/week for 1 hr). We computed reaction time IIV from the Dimensional Change Card Sort Test, Flanker Inhibitory Control and Attention Test (Flanker), and Pattern Comparison Processing Speed Test (PACPS). RESULTS: Compared with the control group, IIV reduced in a processing speed task (PACPS) following CCT alone (mean difference [95% confidence interval]: -0.144 [-0.255 to -0.034], p < 0.01) and CCT with aerobic exercise (-0.113 [-0.225 to -0.001], p < 0.05). Attention (Flanker congruent) IIV was reduced only after CCT with aerobic exercise (-0.130 [-0.242 to -0.017], p < 0.05). CONCLUSIONS: A CCT program promoted cognitive health via reductions in IIV of cognitive performance and combining it with aerobic exercise may result in broader benefits.

A Decade Later on How to "Use It" So We Don't "Lose It": An Update on the Unanswered Questions about the Influence of Activity Participation on Cognitive Performance in Older Age.

Activity engagement is a modifiable factor that has been widely-cited as being good for the aging brain and cognition and represents a valuable target for reducing dementia risk. However, specific issues about activity engagement (mental, social, and physical) and cognition in older adulthood remain, and Bielak [Gerontology 2010;56: 507-519] reviewed seven major methodological and theoretical questions about this relationship. We present an updated reflection on these key questions, focusing on research published in the last 10 years. For some questions, a significant amount of work has been done and conclusions have become clearer; for others, there have been few additions to the literature and our knowledge remains much the same as it was a decade ago. We review the issues identified in the 2010 paper including the directionality and temporal nature of the relationship; whether specific activity domains offer different benefits to cognition and what domain(s) of cognition are affected; variation in the relation by age, gender, or education; potential mechanisms involved; and how activity engagement is assessed. For each, we present the most up-to-date research, discuss remaining challenges and possible future directions. This formal unifying of the information in the field is intended as a guide to support continued progress by spurring on studies addressing specific questions while reminding researchers of critical issues. We conclude with recommendations that future studies investigating the link between activity engagement and cognitive performance in adulthood should consider.

Towards an active and happy retirement? Changes in leisure activity and depressive symptoms during the retirement transition.

Objectives: Retirement is a major life transition in the second half of life, and it can be associated with changes in leisure activity engagement. Although theories of retirement adjustment have emphasized the need to find meaningful activities in retirement, little is known about the nature of changes in leisure activity during the retirement transition and their association with mental health.Methods: Based on four annual waves of the 'Health, Aging and Retirement Transitions in Sweden' study, we investigated the longitudinal association of leisure activity engagement and depressive symptoms using bivariate dual change score models. We distinguished intellectual, social, and physical activity engagement.Results: We found increases in all three domains of activity engagement after retirement. Although level and change of activity and depressive symptoms were negatively associated, the coupling parameters were not significant, thus the direction of effects remains unclear.Conclusion: The results highlight the need to consider the role of lifestyle changes for retirement adjustment and mental health.

There's More than Meets the Eye: Complex Associations of Daily Pain, Physical Symptoms, and Self-Efficacy with Activity in Middle and Older Adulthood.

BACKGROUND: Participation in activities is associated with a range of positive outcomes in adulthood. Research has shown that pain and physical symptoms are associated with less activity in older adults, whereas higher self-efficacy is associated with more activity. Such research tends to examine cross-sectional or long-term between-person change, limiting the opportunity to explore dynamic within-person processes that unfold over shorter time periods. OBJECTIVES: This study aimed to (1) replicate previous between-person associations of self-efficacy with engagement in activity and (2) examine whether daily variation in pain, physical symptoms, and self-efficacy corresponded with daily within-person variation in different types of activity. We predicted that participants would engage in less activity on days when they experienced more pain or physical symptoms than their average (a negative within-person association) and that participants would engage in more activity on days when self-efficacy was higher than average (a positive within-person association). METHODS: This study used an online diary study to assess self- reported daily pain, physical symptoms, self-efficacy, and engagement in activity among 185 adults aged 51-84 years for up to 7 days. Multilevel modelling was used to examine whether between-person (average) and daily within-person variability in pain, physical symptoms, and self-efficacy were associated with social, physical, and mental activity. RESULTS: In line with previous research, between-person self-efficacy was positively associated with social and physical activity. Supporting the hypotheses, within-person self-efficacy was also positively associated with social and physical activity. The results for pain and physical symptoms were less consistent. Between-person pain was positively associated with social activity. Age interactions indicated that within-person pain was negatively associated with social activity and positively associated with physical activity among older adults. Within-person physical symptoms were positively related to social and mental activity. CONCLUSION: Stable individual differences as well as short-term within-person variation in physical and psychological functioning are associated with day-to-day variation in activity. Between-person associations did not always reflect within-person associations (e.g., for pain). These complex associations may be influenced by a range of factors including the type of activity and how it is defined (e.g., specific activities and their difficulty), the type of physical symptoms experienced, and age.

Long-term cognitive correlates of traumatic brain injury across adulthood and interactions with APOE genotype, sex, and age cohorts.

There is continuing debate about long-term effects of brain injury. We examined a range of traumatic brain injury (TBI) variables (TBI history, severity, frequency, and age of injury) as predictors of cognitive outcome over 8 years in an adult population, and interactions with apolipoprotein E (APOE) genotype, sex, and age cohorts. Three randomly sampled age cohorts (20-24, 40-44, 60-64 years at baseline; N = 6333) were each evaluated three times over 8 years. TBI variables, based on self-report, were separately modeled as predictors of cognitive performance using linear mixed effects models. TBI predicted longitudinal cognitive decline in all three age groups. APOE ε4 + genotypes in the young and middle-aged groups predicted lower baseline cognitive performance in the context of TBI. Baseline cognitive performance was better for young females than males but this pattern reversed in middle age and old age. The findings suggest TBI history is associated with long-term cognitive impairment and decline across the adult lifespan. A role for APOE genotype was apparent in the younger cohorts but there was no evidence that it is associated with impairment in early old age. The effect of sex and TBI on cognition varied with age cohort, consistent with a proposed neuroprotective role for estrogen.

Utility of intraindividual reaction time variability to predict white matter hyperintensities: a potential assessment tool for clinical contexts?

Intraindividual variability (IIV) refers to reaction time (RT) variation across the trials of a given cognitive task. Little research has contrasted different measures of IIV or assessed how many RT trials are required to provide a robust measure of the construct. We, therefore, investigated three measures of IIV (raw SD, coefficient of variation, and intraindividual SD statistically removing time-on-task effects) in relation to frontal white matter hyperintensities (obtained through structural MRI) in 415 cognitively normal community-dwelling adults aged 44 to 48 years. Results indicated the three IIV measures did not differ greatly in predictions of white matter hyperintensities, although it is possible that time-on-task effects were influential. As few as 20 trials taking approximately 52 s to administer provided a reliable prediction of frontal white matter hyperintensities. We conclude that future work should evaluate the comparative utility of different IIV measures in relation to persons exhibiting clear neuropathology.

Using Cognitive Intraindividual Variability to Measure Intervention Effectiveness: Results from the Baltimore Experience Corps Trial.

OBJECTIVES: Studies investigating the effectiveness of intervention programs on cognitive ability in older adults are inconsistent; however, these studies generally focus on traditional measures of cognition, and therefore may miss some improvements by not utilizing alternate measures. We evaluate the potential for intraindividual variability in cognitive speed (IIV), a demonstrated sensitive indicator of cognitive functioning, to be used as an index of cognitive plasticity from an intervention. The current study evaluated whether older adults in a school volunteering program showed a reduction in IIV, compared to a low-activity control group over 2 years of exposure. METHOD: Nondemented older adults (n = 336) participated in the Baltimore Experience Corps Trial, an evaluation of a volunteering program conducted at elementary schools designed to increase older adults' physical, cognitive, and social engagement. Participants completed a cognitive battery that included a Stroop task at baseline and after 12 and 24 months. RESULTS: Traditional intent-to-treat analyses did not report significant improvements. Participants who complied at the 80th percentile or above showed a significant reduction in IIV at 24 months, with an additional trend of improved IIV with increased compliance to the treatment protocol, both at 12 months, and at 24 months. Men also showed dose-dependent improvements after 12 months. DISCUSSION: The Experience Corps program resulted in an improvement in cognitive performance as measured by IIV. Analyzing previously collected data with nontraditional measures of cognition, such as IIV, may be a potentially fruitful and cost-effective method for understanding how interventions impact cognition in aging populations.

Evaluating the Consistency of Subjective Activity Assessments and Their Relation to Cognition in Older Adults.

(1) Background: Research examining whether activity engagement is related to cognitive functioning in older adults has been limited to using retrospective reports of activity which may be affected by biases. This study compared two measurements (estimated weekly versus reported daily), and whether these activity assessments were related to cognition in older adults; (2) Methods: Participants from US (n = 199) and Australian (n = 170) samples completed a weekly estimate of activity, followed by 7 consecutive days of daily reporting. Differences between weekly estimates and daily reports were found, such that estimations at the weekly level were lower than self-reported daily information. Multivariate multiple regression was used to determine whether total activity, activity domains and the discrepancy between assessment types (i.e., weekly/daily) predicted cognitive performance across three cognitive domains (fluid, verbal, memory); (3) Results: When activity assessments were totaled, neither predicted cognition; however, when activity was grouped by domain (cognitive, social, physical), different domains predicted different cognitive outcomes. Daily reported cognitive activity significantly predicted verbal performance (ß = 1.63, p = 0.005), while weekly estimated social activity predicted memory performance (ß = -1.81, p = 0.050). Further, while the magnitude of discrepancy in total activity did not significantly predict cognitive performance, domain specific differences did. Differences in physical activity reported across assessments predicted fluid performance (ß = -1.16, p = 0.033); (4) Conclusions: The significant discrepancy between the measurement types shows that it is important to recognize potential biases in responding when conducting activity and cognition research.

How can we not 'lose it' if we still don't understand how to 'use it'? Unanswered questions about the influence of activity participation on cognitive performance in older age--a mini-review.

The 'use it or lose it' hypothesis of cognitive aging predicts that engagement in intellectual, social, and physical activities offers protective benefits from age-related cognitive decline and lowers dementia risk. Although this hypothesis has not yet been supported conclusively, there is some empirical evidence in favor of the proposal. However, a number of questions surrounding the relationship between activity participation and cognitive ability in older adulthood are not yet well answered. This mini-review identifies seven key methodological and theoretical issues that are critical to our understanding and eventual possible promotion of activity participation as a way to maintain cognitive well-being. These include the mechanisms involved, the optimal ways of assessing activity engagement, which cognitive domains receive the most benefit from activity engagement, the temporal nature and the directionality of the relationship, the influence of demographic variables such as age, gender, or education, and whether one activity domain offers the most benefit to cognition. The current knowledge on each of these issues is critically evaluated, including describing what we already know about the issue, and identifying potential difficulties and opportunities that may exist in finding an answer. More studies need to take on the challenge of specifically targeting these issues, as each is essential to moving the field forward.

A Bayesian Analysis of Evidence in Support of the Null Hypothesis in Gerontological Psychology (or Lack Thereof).

OBJECTIVES: Nonsignificant p values derived from null hypothesis significance testing do not distinguish between true null effects or cases where the data are insensitive in distinguishing the hypotheses. This study aimed to investigate the prevalence of Bayesian analyses in gerontological psychology, a statistical technique that can distinguish between conclusive and inconclusive nonsignificant results, by using Bayes factors (BFs) to reanalyze nonsignificant results from published gerontological research. METHODS: Nonsignificant results mentioned in abstracts of articles published in 2017 volumes of 10 top gerontological psychology journals were extracted (N = 409) and categorized based on whether Bayesian analyses were conducted. BFs were calculated from nonsignificant t-tests within this sample to determine how frequently the null hypothesis was strongly supported. RESULTS: Nonsignificant results were directly tested with BFs in 1.22% of studies. Bayesian reanalyses of 195 nonsignificant t-tests found that only 7.69% of the findings provided strong evidence in support of the null hypothesis. CONCLUSIONS: Bayesian analyses are rarely used in gerontological research, and a large proportion of null findings were deemed inconclusive when reanalyzed with BFs. Researchers are encouraged to use BFs to test the validity of nonsignificant results and ensure that sufficient sample sizes are used so that the meaningfulness of null findings can be evaluated.

Using intraindividual variability as an indicator of cognitive improvement in a physical exercise intervention of older women with mild cognitive impairment.

OBJECTIVES: Intervention programs designed to improve cognitive ability in older adults with mild cognitive impairment (MCI) have often focused on physical exercise as a means to improve traditional measures of cognition, with mixed success. Individuals with MCI show high levels of intraindividual variability (IIV) in response speed, and IIV may be sensitive to intervention-related changes. The current study evaluated if participants who participated in a physical activity intervention (aerobic or resistance training) showed a reduction in IIV, compared to a balance and tone control group. METHOD: This study was a secondary analysis of the EXercise for Cognition and Everyday Living (EXCEL) Study. Women Aged 70-80 years with probable MCI (n = 86) participated in a 6-month randomized controlled trial designed to investigate the effects of different physical exercises on cognitive ability. Participants completed 1-back, task switching, and spatial working memory tasks at baseline, 13 weeks (midpoint) and upon completion of the program. RESULTS: Analyses were conducted following both the intent-to-treat principle and complier average casual effect (CACE) modeling. Participants in the intervention group who complied with the program showed reduced IIV on task switching in the CACE models. The intent-to-treat analyses were all nonsignificant. CONCLUSIONS: Physical exercise resulted in improved IIV in older adults with probable MCI, showing that IIV is modifiable by lifestyle engagement. IIV may be a useful complementary index of cognitive plasticity particularly among those with cognitive impairment. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The Impact of a Sustained Cognitive Engagement Intervention on Cognitive Variability: The Synapse Project.

BACKGROUND: Interest in maintaining one's cognitive ability and quality of life through older adulthood has greatly increased in recent years. However, research examining the effectiveness of cognitive engagement interventions on older adults is mixed and the mechanisms behind improving cognition in older age are unknown. It is possible that traditional measures of cognitive outcomes, such as average reaction time, may overlook potential benefits due to a lack of sensitivity in these measures. One alternative metric is intraindividual variability (IIV) in response speed (short-term variations in performance on reaction time tasks), which reflects fluctuations in attention and is a sensitive behavioral measure of neurological integrity that is predictive of future cognitive decline and impairment. OBJECTIVE: The current study aimed to investigate whether IIV was improved in older adults through productive cognitive engagement (i.e., acquisition of new skills) in comparison to receptive engagement (activities that rely upon existing knowledge). METHODS: Participants were 173 typically aging adults aged 60-90 years who were recruited to the Synapse Project and randomly allocated to a productive engagement activity (learning to quilt and/or conduct digital photography) or receptive engagement activity (socializing, or placebo cognitive tasks such as completing crosswords). Participants completed three flanker tasks at baseline and after completing the 14-week intervention program. IIV was calculated as the trial-to-trial variability in responding to congruent and incongruent trials in each task. RESULTS: Neither traditional intent-to-treat nor complier average causal effect modeling analyses showed any significant improvements in IIV for either intervention group. Further, Bayesian analyses showed that there was moderate evidence in favor of the null hypothesis. CONCLUSION: An intensive cognitive activity intervention did not result in a reduction in IIV. We suggest that intervention programs may need to specifically engage cognitive domains associated with IIV (i.e., attention, executive control) for improvements to be observed. Additionally, other design factors such as using a longer duration and/or applying the intervention to atypically aging groups, such as those with mild cognitive impairment, may increase the likelihood of significantly reducing IIV via an intervention.

Can Intraindividual Variability in Cognitive Speed Be Reduced by Physical Exercise? Results From the LIFE Study.

OBJECTIVES: Findings are mixed regarding the potential to improve older adults' cognitive ability via training and activity interventions. One novel sensitive outcome may be intraindividual variability (IIV) in cognitive speed, or moment-to-moment changes in a person's performance. The present article evaluated if participants who participated in a moderate physical activity intervention showed a reduction in IIV, compared with a successful aging education control group. METHOD: For approximately 2.6 years, sedentary adults aged 70-90 years participated in the Lifestyle Interventions and Independence for Elders (LIFE) Study (n = 1,635), a multisite Phase 3 randomized controlled trial to reduce major mobility disability. They completed 4 reaction time tests at baseline and at approximately 24 months post-test. RESULTS: Analyses were conducted following both the intent-to-treat principle and complier average casual effect modeling. Results indicated that participants in the physical activity group did not show a reduction in their IIV. DISCUSSION: The lack of a significant reduction in IIV may be due to the mild nature of the physical activity program and the cognitively healthy sample. It is also possible that other types of lifestyle activity interventions (e.g., social and cognitive engagement) can elicit reductions in IIV for older adults.

Covariation of intraindividual variability in cognitive speed and cognitive performance across young, middle, and older adulthood.

Intraindividual variability (IIV) in cognitive speed, or moment-to-moment changes in ability, is a developmental phenomenon indicative of neurological integrity that increases gradually across adulthood. Past research has shown that IIV negatively covaries with cognitive performance, in which higher IIV at one occasion is associated with poorer cognitive ability at the same occasion. However, this association has been demonstrated only in older adulthood. Further, all past examinations of IIV change with cognitive change did not remove the average or between-person effect from within-person change in IIV. Using the PATH Through Life Study, we evaluated whether there were differences across 3 age cohorts (20-24, 40-44, and 60-64 years at baseline) in the relationship between 8-year change in IIV and change in cognitive ability (N = 7,485). Change in IIV was partitioned into between-person and within-person components, and multilevel models covarying for education, sex, diabetes, hypertension, and anxiety and depressive symptoms were conducted. IIV was negatively related to baseline cognitive performance at the between-person level. Notably, this relation was apparent and, in fact, strongest for those in young adulthood. Level of IIV was also negatively associated with cognitive change, but primarily for the youngest cohort. In contrast to previous research, there was minimal evidence of significant covariation in which within-person changes in IIV were associated with changes in cognitive performance, regardless of age group. Overall, IIV is a stable characteristic negatively associated with cognition in adulthood, but this link may primarily exist at the between-person level. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

What Did You Do Today? Variability in Daily Activities is Related to Variability in Daily Cognitive Performance.

OBJECTIVES: Are the activities we do each day related to fluctuations in our daily cognitive performance? Positive longitudinal associations between cognitive, physical, and social activities and cognitive ability in adulthood are well established. However little is known about how this relationship may operate at the daily level. METHODS: Community-dwelling participants 60-90 years of age (M = 69.41; n = 146) reported their activity participation and completed cognitive tests online for 7 consecutive days. RESULTS: Multilevel models showed that daily activities covaried with daily cognitive performance, indicating fluctuations in the activities that a person engaged in across the week were associated with corresponding changes in their daily speed, memory, and reasoning. This was strongest for social activities where on days when individuals engaged in more routine activities with social-private characteristics than usual, they had higher memory scores and responded faster. DISCUSSION: This information could be particularly relevant to the daily lives of older adults, especially those experiencing cognitive decline.

Two sides of the same coin? Association of variety and frequency of activity with cognition.

The majority of research focused on activity engagement and cognition in older adulthood uses frequency of engagement as the primary metric. Another option is the variety of activities. Carlson et al. (2012) found evidence that a greater variety of activity was protective against cognitive impairment over and above weighted frequency of engagement, suggesting that there may be something unique about activity diversity. The present study compared variety and frequency of activity estimated across 2 different time frames regarding their association with cognitive performance. Community-dwelling participants 60-91 years of age (M = 70.36; n = 199) reported their participation in 57 activities over the past 2 years and logged their daily activities for 1 week. Frequency and variety of activity over 2 years, and across the week were calculated. Structural equation models showed that the frequency indices had a greater number of significant activity factors, and minimally stronger links with the 3 cognitive factors compared to variety of activity. Frequency had stronger associations with cognition for both the 2-year and daily activity estimates, but greater explained variance was only evident when activity was estimated over the past two years. The overall pattern of results was similar for both variety and frequency of activity, highlighting the strong overlap between the 2 indices. Our results support the conclusion that frequency and variety of engagement have similar associations with cognition, and that the most active individuals also have the most diverse engagement. Therefore, a variety index may be sufficient when collecting activity data. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

It's never too late to engage in lifestyle activities: significant concurrent but not change relationships between lifestyle activities and cognitive speed.

Little is known about potential longitudinal relationships between participation in social, physical, and intellectual activities and later cognitive performance. Data from the Victoria Longitudinal Study (n = 530) were used to test whether baseline and change in lifestyle engagement were related to corresponding indicators of cognitive speed (measured by mean-level and intraindividual variability). Regressions based on random effects model estimates showed that cross-sectional activity participation predicted corresponding values of both mean-level and intraindividual variability, but few longitudinal relationships were significant. Overall, a higher frequency of participation in cognitively complex activities was related to faster response times and lower intraindividual variability. Findings suggest that activity level at one point in time may be a more important predictor of cognition than an individual's changes in activity level.

Within-person variability in response speed as an indicator of cognitive impairment in older adults.

Within-person variability may be an important indicator of central nervous system compromise. In this study, within-person variability in response speed was examined in community-dwelling older adults, ages 64-92 years, using a new framework that takes into account both the extent (single versus multiple domains affected) and nature (amnestic versus non-amnestic) of the cognitive impairment. Those with multiple domains of impairment were more variable than those who showed an isolated area of impairment, regardless of whether memory was one of the domains affected. Further, for those with difficulties in two or more non-memory domains, increased variability was most evident in more cognitively demanding situations, when individuals had to manipulate information held briefly in mind, switch cognitive set or inhibit an automatic response. Finally, group differentiation was better achieved when within-person variability as opposed to mean speed of performance was considered.

Different perspectives on measuring lifestyle engagement: a comparison of activity measures and their relation with cognitive performance in older adults.

Given the limitations associated with assessing activity engagement via the frequency of specific activities, it may be valuable to consider the characteristics of an activity. The method of asking individuals to report the amount of time spent engaging in activities that have certain characteristics was compared to a specific activity questionnaire, and a daily diary regarding their relation to cognitive functioning. Participants 60-90 years old (n = 187) completed the activity measurement methods and a series of cognitive tasks. Structural equation models showed that all three activity methods were predictive of adults' cognitive performance, but no measure predicted all outcomes. Each activity measure provided unique information. Notably, the combination of the measurement types predicted more variance than any of the measures alone. There is additional power to predict cognition when multiple activity measurement methods are used, and daily assessment can be a valuable tool to augment traditional specific activity questionnaires.

Cognitive Performance in Adults' Daily Lives: Is There a Lab-Life Gap?

This article addresses the "lab-life gap" in cognitive aging research as an important issue of ecological validity in developmental research. Older adults often function competently in complex everyday situations despite age-related deficits on laboratory-based cognitive tasks. Therefore, to what extent do lab-based cognitive tasks predict real-life outcomes in older adults? Our review shows that although they are similar, measures of everyday cognitive competence predict relevant outcomes beyond basic measures. We provide our perspective on critical questions concerning the relevance of everyday cognitive tests in our ever-changing world, new methods of everyday cognitive assessment, and whether everyday cognition can be improved.