Assessing the Evidential Value of Mental Fatigue and Exercise Research

It has often been reported that mental exertion, presumably leading to mental fatigue, can negatively affect exercise performance; however, recent findings have questioned the strength of the effect. To further complicate this issue, an overlooked problem might be the presence of publication bias in studies using underpowered designs, which is known to inflate false positive report probability and effect size estimates. Altogether, the presence of bias is likely to reduce the evidential value of the published literature on this topic, although it is unknown to what extent. The purpose of the current work was to assess the evidential value of studies published to date on the effect of mental exertion on exercise performance by assessing the presence of publication bias and the observed statistical power achieved by these studies. A traditional meta-analysis revealed a Cohen's dz effect size of - 0.54, 95% CI [- 0.68, - 0.40], p < .001. However, when we applied methods for estimating and correcting for publication bias (based on funnel plot asymmetry and observed p-values), we found that the bias-corrected effect size became negligible with most of publication-bias methods and decreased to - 0.36 in the more optimistic of all the scenarios. A robust Bayesian meta-analysis found strong evidence in favor of publication bias, BFpb > 1000, and inconclusive evidence in favor of the effect, adjusted dz = 0.01, 95% CrI [- 0.46, 0.37], BF10 = 0.90. Furthermore, the median observed statistical power assuming the unadjusted meta-analytic effect size (i.e., - 0.54) as the true effect size was 39% (min = 19%, max = 96%), indicating that, on average, these studies only had a 39% chance of observing a significant result if the true effect was Cohen's dz = - 0.54. If the more optimistic adjusted effect size (- 0.36) was assumed as the true effect, the median statistical power was just 20%. We conclude that the current literature is a useful case study for illustrating the dangers of conducting underpowered studies to detect the effect size of interest.

Time-Based and Event-Based Prospective Memory in Mild Cognitive Impairment and Alzheimer's Disease Patients: A Systematic Review and Meta-analysis

Prospective memory (PM) is the ability to remember to perform planned actions in a future moment and it is of fundamental importance for an independent and autonomous lifestyle from development to late adulthood. Deficits in episodic memory and executive functions, which are involved in PM are characteristic features of mild cognitive impairment (MCI) and Alzheimer's disease (AD). Considering that the number of older adults is drastically increasing over the next decades, it is of great interest to understand how PM decline in healthy older adults and patients with different degree of cognitive decline. The present meta-analysis included 46 studies investigating PM performance in AD patients (17 studies) and people with MCI (24 studies); 5 studies included both clinical conditions in the same article. The 46 studies contributed a total of 63 independent samples and 129 effect sizes from 4668 participants (2115 patients and 2553 controls). Unlike previous reviews of the literature, our results with a larger and updated sample of studies confirmed lower PM abilities in AD compared to MCI and controls, although we did not observe conclusive differences between event-based and time-based PM in patients. Surprisingly, PM deficits shown by MCI and AD patients have decreased across years, in parallel to a reduction of the evidence of publication bias and an increase in the number of observations per task. We propose the use of more reliable research designs as one plausible explanation for the reduction of PM impairments.

The ANTI-Vea-UGR Platform: A Free Online Resource to Measure Attentional Networks (Alertness, Orienting, and Executive Control) Functioning and Executive/Arousal Vigilance

The Attentional Networks Test for Interactions and Vigilance-executive and arousal components (ANTI-Vea) is a computerized task of 32 min duration in the standard format. The task simultaneously assesses the main effects and interactions of the three attentional networks (i.e., phasic alertness, orienting, and executive control) and two dissociated components of vigilance with reasonable reliability (executive and arousal vigilance). We present this free and publicly accessible resource (ANTI-Vea-UGR; https://anti-vea.ugr.es/) developed to easily run, collect, and analyze data with the ANTI-Vea (or its subtasks measuring some attentional and/or vigilance components embedded in the ANTI-Vea). Available in six different languages, the platform allows for the adaptation of stimulus timing and procedure to facilitate data collection from different populations (e.g., clinical patients, children). Collected data can be freely downloaded and easily analyzed with the provided scripts and tools, including a Shiny app. We discuss previous evidence supporting that attention and vigilance components can be assessed in typical lab conditions as well as online and outside the laboratory. We hope this tutorial will help researchers interested in measuring attention and vigilance with a tool useful to collect data from large sample sizes and easy to use in applied contexts.

An umbrella review of randomized control trials on the effects of physical exercise on cognition

Extensive research links regular physical exercise to an overall enhancement of cognitive function across the lifespan. Here we assess the causal evidence supporting this relationship in the healthy population, using an umbrella review of meta-analyses limited to randomized controlled trials (RCTs). Despite most of the 24 reviewed meta-analyses reporting a positive overall effect, our assessment reveals evidence of low statistical power in the primary RCTs, selective inclusion of studies, publication bias and large variation in combinations of pre-processing and analytic decisions. In addition, our meta-analysis of all the primary RCTs included in the revised meta-analyses shows small exercise-related benefits (d = 0.22, 95% confidence interval 0.16 to 0.28) that became substantially smaller after accounting for key moderators (that is, active control and baseline differences; d = 0.13, 95% confidence interval 0.07 to 0.20), and negligible after correcting for publication bias (d = 0.05, 95% confidence interval -0.09 to 0.14). These findings suggest caution in claims and recommendations linking regular physical exercise to cognitive benefits in the healthy human population until more reliable causal evidence accumulates.

Changes in Response Criterion and Lapse Rate as General Mechanisms of Vigilance Decrement: Commentary on McCarley and Yamani (2021)

Multiple theories have used perceptual sensitivity and response criterion indices to explain the decrements in performance across time on task (i.e., vigilance decrement). In a recent study, McCarley and Yamani (2021) offered conceptual and methodological advances to this debate by using a vigilance task that parametrically manipulates noise and signal and analyzes the outcomes with psychometric curves. In the present Commentary, we reanalyze data (N = 553) from a different, already existing vigilance task, the Attentional Networks Test for Interactions and Vigilance-executive and arousal components (ANTI-Vea). Psychometric curves with the ANTI-Vea showed robust changes in response criterion and lapse rate, although not in sensitivity. Our interpretation is that the need to keep the standard in memory in McCarley and Yamani's task could produce a decrease in sensitivity and be related to reduced fidelity of the memory representation rather than to a decrement in perceptual abilities across time on task.

Target-background segregation in a spatial interference paradigm reveals shared and specific attentional mechanisms triggered by gaze and arrows

Recent research has found that eye gaze and arrows yield opposite congruency effects in a spatial interference paradigm, arrows eliciting faster responses when their direction is congruent with their position (standard congruency effect), and gaze producing faster reaction times for incongruent conditions (reversed congruency effect). In addition, we observed by serendipity in a previous study that the standard effect with arrows was reduced when the target appeared within a complex background, presumably because of hindered figure-ground segregation. Under the same conditions, the reversed effect with gaze became more negative. To explain our previous results, we proposed the coexistence of two opposite attentional effects with eye gaze: a standard spatial interference component being common to both arrows and gaze, and a larger social-specific dimension leading to the overall reversion of the effect for gaze. Both in Experiments 1 and 2, gaze or arrow targets were presented after or concurrently with an irrelevant background (asynchronous vs. synchronous conditions, respectively). Consistent with our preregistered hypotheses, the standard effect with arrows was present in the asynchronous condition (automatic figure-ground segregation) but reduced in the synchronous one (difficult figure-ground segregation). Correspondingly with the effect on arrows interference, eye gaze triggered a significant reversed effect in the synchronous condition that decreased in the asynchronous one. These results underline the importance of the figure-ground segregation processes as modulators of the spatial conflict triggered by peripheral targets, and support our two-effect model, according to which gaze shares with nonsocial stimuli a domain-general orienting mechanism, but also triggers distinctive processes. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Prospective and retrospective timing in mild cognitive impairment and Alzheimer's disease patients: A systematic review and meta-analysis

Performance on timing tasks changes with age. Whether these changes reflect a real "clock" problem due to aging or a secondary effect of the reduced cognitive resources of older adults is still an unsettled question. Research on processing of time in aged populations marked by severe mnemonic and/or attentional deficits, such as patients with Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI), may help elucidate the role of cognitive resources in age-related temporal distortions. To this end, we conducted a systematic review and meta-analysis of timing studies in AD and MCI patients; both prospective and retrospective timing tasks were considered and analysed separately. As concerns prospective timing, a first random-effect model showed a medium overall effect of neurodegeneration on timing performance. When considering the role of moderator variables(i.e., neurodegenerative condition, type of measure, participants' age and years of education, interval length, and type of timing task), mean score appeared to be a less sensitive measure than accuracy and variability, and the observed temporal impairment was smaller in older samples. In addition, AD patients only exhibited medium-to-high impairment on prospective timing tasks, whereas MCI patients did not significantly differ from controls. However, assuming a mean age of 70 years old and absolute error as dependent variable, a second fitted meta-regression model predicted a significant outcome also for MCI patients. Concerning retrospective timing, a significant but small effect of neurodegeneration was observed for retrospective judgments. None of the moderators, however, explained between-studies variability. Collectively, our findings highlight a clear deficit in prospective timing for AD patients and underscore several issues that future work should carefully consider to better investigate the effect of MCI on prospective temporal judgements. Results from retrospective timing also point to a possible impairment of retrospective judgments in neurodegenerative conditions, albeit more studies are needed to substantiate this finding.

Musical practice as an enhancer of cognitive function in healthy aging - A systematic review and meta-analysis

Aging is accompanied by cognitive decline, although recent research indicates that the rate of decline depends on multiple lifestyle factors. One of such factors is musical practice, an activity that involves several sensory and motor systems and a wide range of high-level cognitive processes. This paper describes the first systematic review and meta-analysis, to our knowledge, of the impact of musical practice on healthy neurocognitive aging. The inclusion criteria for the review required that studies were empirical works in English or Spanish that they explored the effects of musical practice on older people; they included an assessment of cognitive functions and/or an assessment of brain status; and they included a sample of participants aged 59 years or older with no cognitive impairment or brain damage. This review led to the selection of 13 studies: 9 correlational studies involving older musicians and non-musicians and 4 experimental studies involving short-term musical training programs. The results of the meta-analysis showed cognitive and cerebral benefits of musical practice, both in domain-specific functions (auditory perception) and in other rather domain-general functions. Moreover, these benefits seem to protect cognitive domains that usually decline with aging and boost other domains that do not decline with aging. The origin of these benefits may reside, simultaneously, in the specific training of many of these cognitive functions during musical practice (specific training mechanism), in the improvement of compensatory cognitive processes (specific compensatory mechanism), and in the preservation of general functions with a global influence on others, such as perceptual capacity, processing speed, inhibition and attention (general compensatory mechanism). Therefore, musical practice seems to be a promising tool to reduce the impact of cognitive problems associated to aging.