Exercise interventions preserve hippocampal volume: A meta-analysis.

Hippocampal volume is a marker of brain health and is reduced with aging and neurological disease. Exercise may be effective at increasing and preserving hippocampal volume, potentially serving as a treatment for conditions associated with hippocampal atrophy (e.g., dementia). This meta-analysis aimed to identify whether exercise training has a positive effect on hippocampal volume and how population characteristics and exercise parameters moderate this effect. Studies met the following criteria: (a) controlled trials; (b) interventions of physical exercise; (c) included at least one time-point of hippocampal volume data before the intervention and one after; (d) assessed hippocampal volume using either manual or automated segmentation algorithms. Animal studies, voxel-based morphometry analyses, and multi-modal interventions (e.g., cognitive training or meditation) were excluded. The primary analysis in n = 23 interventions from 22 published studies revealed a significant positive effect of exercise on total hippocampal volume. The overall effect was significant in older samples (65 years of age or older) and in interventions that lasted over 24 weeks and had less than 150 min per week of exercise. These findings suggest that moderate amounts of exercise for interventions greater than 6 months have a positive effect on hippocampal volume including in older populations vulnerable to hippocampal atrophy.

Effects of Physical Activity on Poststroke Cognitive Function: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND AND PURPOSE: Despite the social, health, and economic burdens associated with cognitive impairment poststroke, there is considerable uncertainty about the types of interventions that might preserve or restore cognitive abilities. The objective of this systematic review and meta-analysis was to evaluate the effects of physical activity (PA) training on cognitive function poststroke and identify intervention and sample characteristics that may moderate treatment effects. METHODS: Randomized controlled trials examining the association between structured PA training and cognitive performance poststroke were identified using electronic databases EMBASE and MEDLINE. Intervention effects were represented by Hedges' g and combined into pooled effect sizes using random- and mixed-effects models. Effect sizes were subjected to moderation analyses using the between-group heterogeneity test. RESULTS: Fourteen studies met inclusion criteria, representing data from 736 participants. The primary analysis yielded a positive overall effect of PA training on cognitive performance (Hedges' g [95% confidence interval]=0.304 [0.14-0.47]). Mixed-effects analyses demonstrated that combined aerobic and strength training programs generated the largest cognitive gains and that improvements in cognitive performance were achieved even in the chronic stroke phase (mean=2.6 years poststroke). Positive moderate treatment effects were found for attention/processing speed measures (Hedges' g [confidence interval]=0.37 [0.10-0.63]), while the executive function and working memory domains did not reach significance (P>0.05). CONCLUSIONS: We found a significant positive effect of PA training on cognition poststroke with small to moderate treatment effects that are apparent even in the chronic stroke phase. Our findings support the use of PA training as a treatment strategy to promote cognitive recovery in stroke survivors.

Toward a better understanding of the causal effects of role demands on work-family conflict: A genetic modeling approach.

Over the past several decades, there has been considerable interest in the theoretical causes of work-family conflict (WFC). Most studies have focused on situational determinants, often ignoring the role of personal factors such as disposition and heritable elements. We increase understanding of person versus situation influences on WFC through estimation of the relationship between role demands and WFC after controlling for genetic confounding, measured personality traits, family confounds, and other stable dispositions. Based on twin data from the National Survey of Midlife Development in the United States (MIDUS), we examine the role of genetic factors in explaining variation in WFC (both work interference with family [WIF] and family interference with work [FIW]). Results support WFC has an additive genetic component, accounting for 31% [95% CI 18%, 45%] and 16% [95% CI 2%, 30%] of the variance in WIF and FIW, respectively. In addition, we test two competing hypotheses with regard to the relationship between role demands and WFC. Results support the phenotypic causal relationship for WIF, consistent with the notion the relationship between work demands and WIF reflect situational processes. However, results support the genetic confounding hypothesis for FIW, indicating observed relationships between family demands and FIW are primarily due to genetic factors. Our results provide new insights into the nature of WFC relationships and underscore that ignoring the influence of heritability can bias estimates of role demand effects in WFC research. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Remote worker communication during COVID-19: The role of quantity, quality, and supervisor expectation-setting.

Given the huge increase in remote work that has accompanied the Coronavirus disease (COVID-19) pandemic, understanding predictors of performance and wellbeing among remote workers has never been more timely. Effective communication is commonly cited as key to remote worker success, yet communication variables are rarely incorporated into remote work research. In the present study, we examined the relationship between communication frequency, communication quality, and supervisor-set communication expectations with daily job performance and burnout in an occupationally-diverse sample of employees. We used an experience sampling design and our hypotheses were tested with data collected over a 4-week period with a sample of 471 employees who shifted to full-time remote work due to COVID-19. Results indicated that daily communication quality was associated with daily performance and burnout. In addition, the extent to which supervisors established expectations about communication practices (e.g., expected response times to email) at the onset of the transition to remote work was positively associated with performance, but not burnout. Task interdependence was also tested as a moderator. Task interdependence moderated the relationship between communication quality and performance, such that the relationship was stronger when task interdependence was higher than when it was lower. Task interdependence also moderated the relationship between supervisor-set expectations and performance such that the relationship was stronger when task interdependence was lower than when it was higher. Expected curvilinear relationships between communication frequency and outcomes were not detected. Based on our findings, we provide recommendations for practice and future research. (PsycInfo Database Record (c) 2021 APA, all rights reserved).