Cognitive Interventions for Cognitively Healthy,Mildly Impaired,and Mixed Samples of Older Adults: A Systematic Review and Meta-Analysis of Randomized-Controlled Trials

Cognitive interventions may improve cognition, delay age-related cognitive declines, and improve quality of life for older adults. The current meta-analysis was conducted to update and expand previous work on the efficacy of cognitive interventions for older adults and to examine the impact of key demographic and methodological variables. EBSCOhost and Embase online databases and reference lists were searched to identify relevant randomized-controlled trials (RCTs) of cognitive interventions for cognitively healthy or mildly impaired (MCI) older adults (60+ years). Interventions trained a single cognitive domain (e.g., memory) or were multi-domain training, and outcomes were assessed immediately post-intervention using standard neuropsychological tests. In total, 279 effects from 97 studies were pooled based on a random-effects model and expressed as Hedges’ g (unbiased). Overall, results indicated that cognitive interventions produce a small, but significant, improvement in the cognitive functioning of older adults, relative to active and passive control groups (g = 0.298, p < .001, 95% CI = 0.248–0.347). These results were confirmed using multi-level analyses adjusting for nesting of effect sizes within studies (g = 0.362, p < .001, 95% CI = 0.275, 0.449). Age, education, and cognitive status (healthy vs. MCI) were not significant moderators. Working memory interventions proved most effective (g = 0.479), though memory, processing speed, and multi-domain interventions also significantly improved cognition. Effects were larger for directly trained outcomes but were also significant for non-trained outcomes (i.e., “transfer effects”). Implications for future research and clinical practice are discussed. This project was pre-registered with PROSPERO (#42016038386).     

Transdiagnostic and Transcultural: Pilot Study of Unified Protocol for Depressive and Anxiety Disorders in Japan

Unified protocol (UP) is a transdiagnostic cognitive behavior therapy for emotional disorders. It remains unknown whether UP is applicable for use in non-Western countries and for depressive disorders. We therefore examined its feasibility for a Japanese clinical population using this clinical trial design, which is multicentered, open-labeled, and single-armed (Clinical registry: UMIN000008322). The primary outcome was severity of anxiety symptoms, as assessed using Structured Interview Guide for the Hamilton Anxiety Rating Scale. Secondary outcomes were depressive symptoms, clinical global impression, functioning, quality of life, affectivity, emotion regulation, and adverse events. Of the 28 prospective participants, 17 were eligible and enrolled (depressive disorders = 9, anxiety disorders = 8). Severity of anxiety symptoms, which decreased significantly after the intervention, remained low for 3 months (Hedges’ g = 1.29, 95% CI = 0.56–2.06). Similar tendencies were observed for secondary outcome measures. No severe adverse event occurred. Two participants dropped out of the intervention. High treatment adherence and interrater reliability were confirmed. Results suggest the feasibility of UP in the Japanese context sufficient to warrant a larger clinical trial.     

Examining the roles of experiential avoidance and cognitive fusion on the effects from mindfulness to athlete burnout: A longitudinal study

ObjectivesAthlete burnout is a maladaptive outcome that is potentially detrimental for performance and wellbeing. Cross-sectional evidence suggests that mindfulness might be associated with athlete burnout via experiential avoidance and cognitive fusion. In the current study, we extend knowledge of these hypothesized mediational pathways using a longitudinal design.MethodsData was collected at three occasions with a three-month interval. A final sample of 280 elite Chinese athletes aged 15–32 years (M_age = 19.13; SD = 2.92; Female = 130) reported their mindfulness at Time 1, experiential avoidance and cognitive fusion at Time 2, and athlete burnout at Time 3. Structural equation modelling was adopted to examine the mediating roles of experiential avoidance and cognitive fusion on the effects from mindfulness to athlete burnout.ResultsWe found statistically meaningful directs effects from mindfulness (Time 1) to experiential avoidance and cognitive fusion (Time 2), which in turn influenced athlete burnout (Time 3). However, the direct effect from mindfulness at Time 1 to athlete burnout at Time 3 was non-significant. The indirect effects of experiential avoidance and cognitive fusion on the effects from mindfulness to athlete burnout were significant, providing longitudinal evidence that these two variables contribute meaningfully to the mindfulness-burnout pathway.ConclusionWith initial evidence for the mediating effects of experiential avoidance and cognitive fusion, future studies could consider using experimental designs to examine the potential changing mechanisms of mindfulness on reducing athlete burnout.     

Effects of a single bout of moderate-to-vigorous physical activity on executive functions in children with attention-deficit/hyperactivity disorder: A systematic review and meta-analysis

ObjectivesThe aim of this study was to systematically review the literature investigating the acute effects of moderate-to-vigorous physical activity (MVPA) on executive functions (EFs) in children with attention-deficit/hyperactivity disorder (ADHD) and perform a meta-analysis of the effects of MVPA on task components that require lower and higher EF demand in this population.MethodsThe systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Six electronic databases, i.e., PubMed, Scopus, Web of Science, Embase, SPORTDiscus, and Education Resources Information Center (ERIC), were searched for eligible studies. Random-effects weights were used to pool the effect sizes. Publication bias was assessed by Egger’s regression test and Rosenthal’s fail-safe N. This study is registered on PROSPERO, number CRD42020184082.ResultsThe electronic database search yielded 12 studies, which met the inclusion criteria, comprising a total of 375 participants. Eleven studies with data from 275 participants were included in the meta-analysis to examine the acute effects of MVPA on tasks with lower and higher EF demand. A single bout of MVPA had a small positive effect on tasks with lower (n = 10, g = 0.32, 95% CI = 0.123–0.517) and higher (n = 10, g = 0.25, 95% CI = 0.13–0.371) EF demand. No publication bias was found.ConclusionsA single bout of MVPA may have a general facilitative effect on cognition, indicating that acute MVPA may be a transient nonpharmacological adjunctive treatment for childhood ADHD.     

Exercise training and health-related quality of life in generalized anxiety disorder

ObjectiveTo quantify the effects of six-weeks of resistance (RET) and aerobic exercise training (AET) on quality of life (QoL) among sedentary women with Generalized Anxiety Disorder (GAD).DesignData from our published randomized controlled trial of the effects of six-weeks of either RET or AET among GAD patients were analyzed.MethodThirty women with GAD were randomized to either six weeks of twice-weekly lower-body weightlifting or cycling, or wait-list control (WL). SF-36 subscales assessed dimensions of QoL. Hedges’ d effect sizes (95%CIs) quantified the magnitude of change in response to exercise training compared to WL.ResultsRET significantly improved role-physical (d = 1.04; 95%CI: [0.11–1.97]), role-emotional (d = 0.96; [0.04–1.89]), and mental health (d = 1.05; [0.11–1.98]). AET resulted in significant improvements in physical function (d = 1.31; [0.34–2.27]) and vitality (d = 0.93; [0.01–1.85]).ConclusionsExercise training improves dimensions of QoL among GAD patients. The largest effects were observed for role impairments, physical function, vitality, and mental health.     

Are Shunt Revisions Associated with IQ in Congenital Hydrocephalus? A Meta -Analysis

Although it is generally acknowledged that shunt revisions are associated with reductions in cognitive functions in individuals with congenital hydrocephalus, the literature yields mixed results and is inconclusive. The current study used meta-analytic methods to empirically synthesize studies addressing the association of shunt revisions and IQ in individuals with congenital hydrocephalus. Six studies and three in-house datasets yielded 11 independent samples for meta-analysis. Groups representing lower and higher numbers of shunt revisions were coded to generate effect sizes for differences in IQ scores. Mean effect size across studies was statistically significant, but small (Hedges’ g = 0.25, p < 0.001, 95 % CI [0.08, 0.43]) with more shunt revisions associated with lower IQ scores. Results show an association of lower IQ and more shunt revisions of about 3 IQ points, a small effect, but within the error of measurement associated with IQ tests. Although clinical significance of this effect is not clear, results suggest that repeated shunt revisions because of shunt failure is associated with a reduction in cognitive functions.     

Do group-based mindfulness meditation programs enhance executive functioning? A systematic review and meta-analysis of the evidence

Research examining the effects of group-based mindfulness interventions on executive functioning have yielded inconsistent findings, with some reports of enhanced performance and other reports of null findings. Inconsistencies in the literature may be due to methodological differences across studies, including the type of control group employed and sample characteristics (e.g., clinical vs. non-clinical samples). The current systematic review and meta-analysis examined the effect of group-based mindfulness programs on executive functioning in persons 18+ years of age. Following the standards for systematic review, a total of 29 studies were included in the meta-analysis, of which 21 comparisons contributed to the analysis of inhibition; nine to working memory; nine to attention shifting; and four to the analysis of verbal fluency. After removing outliers, random effects models suggested a small but significant synthesized effect of group-mindfulness training on overall executive functioning (95% CI = 0.256, 0.725). Examination of executive subdomains after removing outliers suggested a small, statistically significant effect for inhibition (95% CI = 0.055, 0.387), working memory (95% CI = 0.010, 0.437), and verbal fluency (95% CI = 0.071, 1.931). No significant pooled effects were found for attention shifting. A priori subgroup analysis by randomization, type of control group, and sample cohort revealed inconsistent results. Overall, the current review suggests that the effect of group-based mindfulness training on executive functioning is not robust.     

Effects of motor-cognitive coordination training and cardiovascular training on motor coordination and cognitive functions

ObjectivesNumerous recent studies showed that physical training can enhance cognitive abilities, such as attention, spatial ability, memory performance, and executive functions. However, most of these studies focused on the efficiency of cardiovascular training, whereas evidence for combined motor-cognitive training emphasizing coordination abilities is scarce. Therefore, the aim of the present study was to investigate the effects of motor-cognitive coordination training and moderate cardiovascular training on cognitive functions and to test whether these effects were related to participant's fitness level.Design and methodWe tested 50 physically active (mean age = 23.5 years, SD = 3.2) and 56 sedentary participants (mean age = 23.4 years, SD = 3.2) in a pretest-training-posttest design with 12 sessions of moderate cardiovascular training (≈60% HRmax) or motor-cognitive coordination training. The training groups were compared to a passive control group. At pretest and posttest, participants performed an untrained motor-cognitive coordination task, measures of executive control (cognitive flexibility, inhibition, working memory), spatial ability, and fluid intelligence.Results and conclusionsWe found improved coordination abilities in the coordination training group, but no transfer of training to cognitive measures in physically active participants. However, sedentary participants showed larger improvements in terms of inhibition in the coordination training group compared to the remaining groups, while the cardiovascular training group improved in cognitive flexibility compared to the remaining groups. In sum, there are positive but differential effects of cardiovascular training and coordination training on cognitive performance in sedentary young participants, suggesting that coordination training may be a useful intervention especially for individuals that cannot perform cardiovascular training.     

A meta-analysis of the effects of antidepressants on cognitive functioning in depressed and non-depressed samples

A thorough understanding of the cognitive effects of antidepressant medications is essential given their frequency of use. This meta-analysis was conducted to investigate whether antidepressants differentially affect the various domains of cognitive functioning for depressed and non-depressed participants. An electronic search of PsycInfo, Medline and Google Scholar was conducted for all journal articles published between January 1998 and January 2017. Thirty-three studies were included enabling calculation of Hedges’ g using a random effects model for the cognitive domains of divided attention, executive function, expressive language, immediate memory, perceptual motor skills, processing speed, recent memory, sustained attention, visuospatial-constructional skills and working memory. Results revealed that overall, antidepressants have a modest, positive effect on divided attention, executive function, immediate memory, processing speed, recent memory and sustained attention for depressed participants. Selective serotonin reuptake inhibitors (SSRI’s) were found to have the greatest positive effect on cognition for depressed participants, as compared to the other classes of antidepressants analysed. Antidepressants did not significantly affect cognitive function in non-depressed participants.     

Physical fitness,cognitive functioning and academic achievement in healthy adolescents

PurposeExamine the association between health-related physical fitness (cardiorespiratory fitness and muscular fitness) and skill-related physical fitness (speed-agility) and both cognitive functions and academic achievement in adolescents (12–15 years).MethodsData of 423 Dutch adolescents were analyzed (46.8% boys, age = 13.45 ± 0.43 years). Physical fitness was assessed using five subtests of the Eurofit test battery measuring cardiorespiratory fitness (20 m Shuttle Run Test), muscular fitness (Broad Jump and Sit-Ups) and speed-agility (10 × 5 m Shuttle Run Test and Plate Tapping Test). Cognitive functions were assessed by the Digit Span Task, the Grid Task and an adapted version of the Attention Network Test. Finally, academic achievement was assessed by two standardized tests assessing mathematic skills and language skills. Multilevel regression analyses were performed in MlWin to examine the relations of interest adjusting for sex and age.ResultsMultilevel regression analysis showed that speed-agility was significantly related to visuospatial working memory (β = 0.159; p = 0.014), information processing and control (β = 0.238; p < 0.001) and interference control (β = 0.156; p = 0.039), but not to the other cognitive or academic achievement outcomes. Cardiorespiratory fitness and muscular fitness were not related to any of the cognitive or academic achievement outcomes.ConclusionThe results suggest that skill-related physical fitness is related to cognitive functions and health-related physical fitness is not. Therefore it can be argued that improved levels of skill-related physical fitness may lead to improved cognitive functioning.     

Acute exercise and children’s cognitive functioning: What is the optimal dose of cognitive challenge?

Acute bouts of exercise have the potential to benefit children’s cognition. Inconsistent evidence on the role of qualitative exercise task characteristics calls for further investigation of the cognitive challenge level in exercise. Thus, the study aim was to investigate which “dose” of cognitive challenge in acute exercise benefits children’s cognition, also exploring the moderating role of individual characteristics. In a within-subject experimental design, 103 children (M_age = 11.1, SD = 0.9, 48% female) participated weekly in one of three 15-min exergames followed by an Attention Network task. Exergame sessions were designed to keep physical intensity constant (65% HR_max) and to have different cognitive challenge levels (low, mid, high; adapted to the ongoing individual performance). ANOVAs performed on variables that reflect the individual functioning of attention networks revealed a significant effect of cognitive challenge on executive control efficiency (reaction time performances; p = .014, ƞ²_p = .08), with better performances after the high-challenge condition compared to lower ones (ps < .015), whereas alerting and orienting were unaffected by cognitive challenge (ps > .05). ANOVAs performed on variables that reflect the interactive functioning of attention networks revealed that biological sex moderated cognitive challenge effects. For males only, the cognitive challenge level influenced the interactive functioning of executive control and orienting networks (p = .004; ƞ²_p = .07). Results suggest that an individualized and adaptive cognitively high-challenging bout of exercise is more beneficial to children’s executive control than less challenging ones. For males, the cognitive challenge in an acute bout seems beneficial to maintain executive control efficiency also when spatial attention resources cannot be validly allocated in advance. Results are interpreted referring to the cognitive stimulation hypothesis and arousal theory.     

Effects of school-based interventions on motivation towards physical activity in children and adolescents: A systematic review and meta-analysis

IntroductionAssuming that motivation is the key to initiate and sustain beneficial health behaviors, the aim of this systematic review was to analyze the effects of school-based physical activity interventions on a variety of motivational outcomes towards PA in school-aged children and adolescents.MethodsA comprehensive literature search was carried out in six electronic databases to identify randomized controlled trials and quasi-experimental trials examining the effects of PA interventions implemented during the regular school day, e.g., during physical education lessons or lunch breaks. Primary outcomes of interest were students' motivation, basic psychological needs, goal orientation, enjoyment, and motivational teaching climate in physical education. Meta-analyses were conducted for these outcomes using Comprehensive Meta-analysis software. Secondarily, intervention effects on students' PA behaviors were examined and the findings summarized narratively. Methodological quality of studies was evaluated using the Cochrane Collaboration's tool for assessing risk of bias for randomized trials; certainty of evidence on outcome level was evaluated using the GRADE approach.ResultsIn total, 57 studies carried out between 2001 and 2018 were included in this review. Sixteen individual meta-analyses were performed and revealed significant pooled effects for the outcomes enjoyment (g = 0.310), perceived autonomy (g = 0.152), identified regulation (g = 0.378), intrinsic motivation (g = 0.419), self-determination index (g = 0.672), task/mastery climate (g = 0.254), ego/performance climate (g = −0.438), autonomy supportive climate (g = 0.262), task goal orientation (g = 1.370), ego goal orientation (g = −0.188). The narrative data synthesis indicated an increase in students' PA behavior. The overall risk of bias was high across all studies and certainty of evidence of meta-analyzed outcomes ranged from very low to moderate. Moderate certainty of evidence was found for ego/performance climate and ego goal orientation. Conclusions: Meta-analyses suggest that school-based PA interventions may be effective in increasing a variety of motivational outcomes. However, the certainty of evidence was limited in the majority of outcomes. Further research is needed to identify effective intervention strategies that increase students’ motivation towards PA.     

Internet-delivered transdiagnostic and tailored cognitive behavioral therapy for anxiety and depression: a systematic review and meta-analysis of randomized controlled trials

Anxiety and depressive disorders are often comorbid. Transdiagnostic and tailored treatments seem to be promising approaches in dealing with comorbidity. Although several primary studies have examined the effects of Internet-delivered cognitive behavior therapy (iCBT) for anxiety and depression, no meta-analysis including different types of iCBT that address comorbidity has been conducted so far. We conducted systematic searches in databases up to 1 July 2016. Only randomized trials comparing transdiagnostic/tailored iCBT for adult anxiety and/or depression with control groups were included. Nineteen randomized trials with a total of 2952 participants that met inclusion criteria were analyzed. The quality of the studies was high, however the blinding criteria were not fulfilled. The uncontrolled effect size (Hedges’ g) of transdiagnostic/tailored iCBT on anxiety and depression outcomes was large and medium for quality of life. The controlled effect size for iCBT on anxiety and depression outcomes was medium to large (anxiety: g = .82, 95% CI: .58–1.05, depression: g = .79, 95% CI: .59–1.00) and medium on quality of life (g = .56, 95% CI: .37–.73). Heterogeneity was small (quality of life) to moderate (anxiety, depression). There was a large effect on generic outcome measures and a moderate effect on comorbidities. When compared to disorder-specific treatments there were no differences on anxiety and quality of life outcomes, however there were differences in depression outcomes. Transdiagnostic and tailored iCBT are effective interventions for anxiety disorders and depression. Future studies should investigate mechanisms of change and develop outcome measures for these interventions.     

Functional Disability in Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

Accumulating evidence suggests that the pre-dementia syndrome mild cognitive impairment (MCI) is characterized by decrements in instrumental activities of daily living (IADL). The current review was a quantitative synthesis of the available literature to objectively characterize IADL disability in MCI while clarifying inconsistencies in findings across studies. It was hypothesized that individuals with MCI would display significantly greater functional impairment relative to cognitively intact controls. Candidate moderators specified a priori included functional assessment approach, MCI subtype, depressive symptoms, and language conducted. Online databases (PubMed/MEDLINE and PsycINFO) and reference lists were searched to identify peer-reviewed publications assessing IADL in MCI compared to normal aging. A total of 151 effect sizes derived from 106 studies met inclusionary criteria (N?=?62,260). Random effects models yielded a large overall summary effect size (Hedges’ g?=?0.76, 95 % confidence interval: 0.68???0.83, p?<?.001) confirmed in multi-level analyses adjusted for nesting of effect sizes within studies (g?=?0.78, 95 % confidence interval: 0.69???0.87). Functional assessment strategy and MCI subtype were significant moderators of effect size, whereas depressive symptoms and language were not. Results convincingly demonstrate that MCI is associated with significant difficulties in the performance of complex everyday tasks. It appears that functional decline, like cognitive decline, exists on a continuum from healthy aging to dementia onset. Implications for clinical practice and research priorities are discussed.     

Diverse multi-week physical activity programs reduce ADHD symptoms: A systematic review and meta-analysis

ObjectivePhysical activity (PA) has been proposed as an adjunct treatment and secondary prevention intervention for attention-deficit hyperactivity/impulsivity disorder (ADHD) and oppositional defiant disorder (ODD). However, meta-analyses testing effects on symptoms and functional impairment have yielded conflicting results.MethodsA systematic search of eight databases yielded 15 randomized controlled trial and 2 quasi-experimental design studies—including N = 881 youth (M = 9.75 years, 71% male)—that tested the effects of multi-week PA programs on symptoms and impairment of children with [or at-risk for] ADHD and/or ODD.ResultsRandom effects meta-analyses favored PA groups on omnibus ADHD measures (g = −0.42, 95%CI[-0.62;-0.21]), combined ADHD symptoms (g = −0.50, 95%CI[-0.82;-0.17]), inattention (g = −0.41,95%CI[-0.82; 0.00]), and hyperactivity/impulsivity (g = −0.30, 95%CI[-0.56;-0.04]). Heterogeneity was moderate across studies (I² = 49%, 95%CI[12%-to-70%]). Significant differences favored PA programs whether inclusion required diagnosis, programs augmented frontline treatments, and active or passive comparison groups were utilized.ConclusionDiverse PA programs can reduce ADHD symptoms, especially where they intentionally pursue this end.     

Effects of psychological interventions on competitive anxiety in sport: A meta-analysis

ObjectivesThis study reviewed the effects of psychological interventions on competitive anxiety in sport.DesignMeta-analysis and systematic review.MethodPsycINFO, PsycARTICLES, SPORTDiscus, Web of Science, ProQuest, and Sage databases were searched for experimental studies that fulfilled the inclusion criteria. Risk of bias was assessed using the 12 criteria Cochrane Review Book Group tool. Hedge's g and 95% confidence intervals (CIs) were calculated and pooled using a random effects model employing the Hartung-Knapp-Sidik-Jonkman (HKSJ) method.ResultsThe search strategy identified 37 studies which fulfilled the inclusion criteria. The meta-analysis was conducted on 34 studies after removal of outliers. The results showed an overall small to medium-sized effect for psychological interventions on competitive anxiety in athletes (g = −0.42; 95% CI, −0.58 to −0.25). Subsequent subgroup analyses showed that this finding was robust regardless of experimental design, anxiety measure, anxiety type, gender, country, sport, intervention component, intervention delivery method, and intervention duration. The results indicated that the effects might be greater for athletes of higher levels of competition as compared to those from lower levels of competition. Separate meta-analyses also suggested that there were medium to large-sized effects for cognitive anxiety (g = −0.54) and self-confidence (g = 0.55) intensity, and a small to medium-sized effect for somatic anxiety (g = −0.36) intensity.ConclusionThe findings from this review study provide a robust evidence base for the use of psychological interventions to help reduce competitive anxiety in athletes. Future studies need to investigate how psychological interventions might affect the directional interpretation of anxiety symptoms.     

Measurement of cognitive functions in experts and elite athletes: A meta‐analytic review

An extraordinary physiological capacity combined with remarkable motor control, perception, and cognitive functioning is crucial for high performance in sports. Tests that assess the physical abilities are already well established. Moreover, a growing area of research evolved in the recent past that is particularly concerned with the basic cognitive functions by means of neurocognitive tests in experts and elite athletes. The aim of this meta‐analysis (k = 19) is to quantify differences among experts and nonexperts as well as elite athletes and non‐elite athletes. In addition, it aims to assemble and compare previous research and analyze possible differences in cognitive functions depending on age, skill level, and used cognitive tasks. Overall, the mean effect size was small to medium (r = 0.22), indicating superior cognitive functions in experts and elite athletes. The factor of skill definition significantly differentiates the cognition–expertise relationship. In contrast, differences in age groups and cognitive areas appeared but were not significant. Future research should prefer the elite rather than the expert definition and distinguish between high‐performance and amateur athletes. Furthermore, the findings suggest that it can be beneficial for coaches and sport clubs to integrate cognitive tests as an additional tool for scouting and for optimizing the athletic development of their players.     

Sleep interventions for performance,mood and sleep outcomes in athletes: A systematic review and meta-analysis

Sleep is fundamental to sports performance and other health outcomes such as mental wellbeing. This systematic review explored the effects of sleep interventions implemented among athletes on performance, sleep, and mood outcomes. Five databases were searched, returning 5996 records for screening. Of these, 27 articles met the inclusion criteria (16 controlled deigns, 11 uncontrolled; athletes n = 617; male n = 432, female n = 93, non-binary/other n = 0 or not reported n = 92). Narrative synthesis of all studies based on intervention type suggested that sleep hygiene, assisted sleep, and sleep extension interventions may be associated with improved sleep, performance, and mood outcomes. Twelve controlled trials were eligible for quantitative meta-analysis, investigating the effect of sleep interventions on athlete sleep, performance, and negative affect, compared to controls post-intervention. Utilizing random-effects meta-analyses, sleep interventions improved subjective sleep quality (g = 0.62, 95% CI [0.21, 1.02]), reduced sleepiness (g = 0.81, 95% CI [0.32, 1.30]) and decreased negative affect (g = 0.63, 95% CI [0.27, 0.98]), but did not appear to influence subjective sleep duration. No effects were identified for objective sleep measures (e.g., actigraphy), or aerobic/anaerobic performance indices. While sleep interventions may offer some benefit to athletes, caution is warranted given limitations of the extant research relating to small, non-representative studies with methodological concerns.     

Mindfulness-based interventions with youth: A comprehensive meta-analysis of group-design studies

The treatment effects of Mindfulness-Based Interventions (MBIs) with youth were synthesized from 76 studies involving 6121 participants. A total of 885 effect sizes were aggregated using meta-regression with robust variance estimation. Overall, MBIs were associated with small treatment effects in studies using pre-post (g = 0.305, SE = 0.039) and controlled designs (g = 0.322, SE = 0.040). Treatment effects were measured after a follow-up period in 24 studies (n = 1963). Results demonstrated that treatment effects were larger at follow-up than post-treatment in pre-post (g = 0.462, SE = 0.118) and controlled designs (g = 0.402, SE = 0.081). Moderator analyses indicated that intervention setting and intervention dosage were not meaningfully related to outcomes after controlling for study design quality. With that said, the between-study heterogeneity in the intercept-only models was consistently small, thus limiting the amount of variance for the moderators to explain. A series of exploratory analyses were used to investigate the differential effectiveness of MBIs across four therapeutic process domains and seven therapeutic outcome domains. Small, positive results were generally observed across the process and outcome domains. Notably, MBIs were associated with moderate effects on the process variable of mindfulness in controlled studies (n = 1108, g = 0.510). Limitations and directions for future research and practice are discussed.