Confirmatory factor analysis (CFA) has been frequently applied to executive function measurement since first used to identify a three-factor model of inhibition, updating, and shifting; however, subsequent CFAs have supported inconsistent models across the life span, ranging from unidimensional to nested-factor models (i.e., bifactor without inhibition). This systematic review summarized CFAs on performance-based tests of executive functions and reanalyzed summary data to identify best-fitting models. Eligible CFAs involved 46 samples ( = 9,756). The most frequently accepted models varied by age (i.e., preschool = one/two-factor; school-age = three-factor; adolescent/adult = three/nested-factor; older adult = two/three-factor), and most often included updating/working memory, inhibition, and shifting factors. A bootstrap reanalysis simulated 5,000 samples from 21 correlation matrices (11 child/adolescent; 10 adult) from studies including the three most common factors, fitting seven competing models. Model results were summarized as the mean percent accepted (i.e., average rate at which models converged and met fit thresholds: CFI ≥ .90/RMSEA ≤ .08) and mean percent selected (i.e., average rate at which a model showed superior fit to other models: ΔCFI ≥ .005/.010/ΔRMSEA ≤ -.010/-.015). No model consistently converged and met fit criteria in all samples. Among adult samples, the nested-factor was accepted (41-42%) and selected (8-30%) most often. Among child/adolescent samples, the unidimensional model was accepted (32-36%) and selected (21-53%) most often, with some support for two-factor models without a differentiated shifting factor. Results show some evidence for greater unidimensionality of executive function among child/adolescent samples and both unity and diversity among adult samples. However, low rates of model acceptance/selection suggest possible bias toward the publication of well-fitting but potentially nonreplicable models with underpowered samples. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Mild Traumatic Brain Injury (mTBI), also known as concussion, has become a growing public health concern, prevalent in both athletic and military settings. Many researchers have examined post-mTBI neuropsychological outcomes, leading to multiple meta-analyses amalgamating individual study results. Objective: Considering the plethora of meta-analytic findings, the next logical step stands as a systematic review of meta-analyses, effectively reporting key moderators that predict post-mTBI neuropsychological outcomes. Method: A systematic review of reviews yielded 11 meta-analyses meeting inclusion criteria (i.e., English-language systematic reviews/meta-analyses covering post-mTBI observational cognitive research on late adolescents/adults), with their findings qualitatively synthesized based on moderator variables (i.e., cognitive domain, time since injury, past head injury, participant characteristics, comparison group, assessment technique, and persistent symptoms). Results: The overall effect sizes ranged for both general (range: .07-.61) and sports-related mTBI (range: .40 -.81) and differed both between and within cognitive domains, with executive functions appearing most sensitive to multiple mTBI. Cognitive domains varied in recovery rates, but overall recovery occurred by 90 days postinjury for most individuals and by 7 days postinjury for athletes. Greater age/education and male gender produced smaller effects sizes, and high school athletes suffered the largest deficits post-mTBI. Controlgroup comparisons yielded larger effects than within-person designs, and assessment techniques had limited moderating effects. Conclusions: Overall, meta-analytic review quality remained low with few studies assessing publication or study quality bias. Meta-analyses consistently identified adverse acute mTBI-related effects and fairly rapid symptom resolution. Future meta-analyses should better operationally define cognitive constructs to produce more consistent effect estimates across domains. Keywords: mTBI, concussion, mild traumatic brain injury, cognition, neuropsychologySupplemental materials: http://dx.doi.org/10.1037/neu0000037.supp Mild Traumatic Brain Injury (mTBI), also known as concussion, stands as a prevalent neurotrauma within the general population , increasingly common in both athletic (Coronado, McGuire, Faul, Sugerman, & Pearson, 2012) and military settings (Iverson, Langlois, McCrea, & Kelly, 2009). The rates and consequences of mTBI have become progressively more publicized, both in sports (Moser, 2007) and in modern conflicts (Hayward, 2008). Highly prevalent in American football (Gessel, Fields, Collins, Dick, & Comstock, 2007), mTBI now represents a signature injury of the sport. Although its seriousness has been historically underestimated, repeated mTBIs among young athletes have been linked to significant neurodegeneration long after retiring from play (Gavett, Stern, & McKee, 2011;Guskiewicz et al., 2005;McKee et al., 2009). In 2011, Dave Duerson, a former American football safety, took his o...

In subjective cognitive decline (SCD), older adults present with concerns about self-perceived cognitive decline but are found to have clinically normal function. However, a significant proportion of those adults are subsequently found to develop mild cognitive impairment, Alzheimer's dementia or other neurocognitive disorder. In other cases, SCD may be associated with mood, personality, and physical health concerns. Regardless of etiology, adults with SCD may benefit from interventions that could enhance current function or slow incipient cognitive decline. The objective of this systematic review and meta-analysis, conducted in accordance with the PRISMA guidelines, is to examine the benefits of non-pharmacologic intervention (NPI) in persons with SCD. Inclusion criteria were studies of adults aged 55 + with SCD defined using published criteria, receiving NPI or any control condition, with cognitive, behavioural, or psychological outcomes in controlled trails. Published empirical studies were obtained through a standardized search of CINAHL Complete, Cochrane Central Register of Controlled Trials, MEDLINE with Full Text, PsycINFO, and PsycARTICLES, supplemented by a manual retrieval of relevant articles. Study quality and bias was determined using PEDro. Nine studies were included in the review and meta-analysis. A wide range of study quality was observed. Overall, a small effect size was found on cognitive outcomes, greater for cognitive versus other intervention types. The available evidence suggests that NPI may benefit current cognitive function in persons with SCD. Recommendations are provided to improve future trials of NPI in SCD.

Both treatments improved executive functions, but CT presented a potential advantage at improving executive functions. Improvements in executive functions differed depending on construct for CT, whereas each construct produced similar, modest effect sizes for PE. Publication bias and study quality variability potentially bias these conclusions, as lower quality studies likely produced inflated effect sizes.

We argue that making accept/reject decisions on scientific hypotheses, including a recent call for changing the canonical alpha level from p = 0.05 to p = 0.005, is deleterious for the finding of new discoveries and the progress of science. Given that blanket and variable alpha levels both are problematic, it is sensible to dispense with significance testing altogether. There are alternatives that address study design and sample size much more directly than significance testing does; but none of the statistical tools should be taken as the new magic method giving clear-cut mechanical answers. Inference should not be based on single studies at all, but on cumulative evidence from multiple independent studies. When evaluating the strength of the evidence, we should consider, for example, auxiliary assumptions, the strength of the experimental design, and implications for applications. To boil all this down to a binary decision based on a p-value threshold of 0.05, 0.01, 0.005, or anything else, is not acceptable.