Exploring Risk Perception, Mental Health, Mental Fatigue, Stigma, and the Quality of Life among UAE Healthcare Workers during the COVID-19 Pandemic: A National Multicentric Cross-Sectional Study.

Globally, the COVID-19 pandemic has presented serious mental health challenges for healthcare professionals. This study investigated the mental health, mental fatigue, quality of life, and stigma of social discrimination among healthcare workers in the United Arab Emirates (UAE) during the COVID-19 pandemic. A correlational, cross-sectional, multi-centric design was employed to collect data from 1383 healthcare workers across various healthcare settings. Participants were recruited using combined cluster and purposive sampling techniques. Standardized questionnaires, including the COVID-19 Pandemic Mental Health Questionnaire (CoPaQ), the Mental Fatigue Scale (MFS), the Social Discrimination Scale-Stigma Subscale (SDS), and the WHO Quality of Life Questionnaire-Brief (WHOQOL-BREF), were administered to assess the study variables. The results indicated significant mental health impacts, with high average scores for post-traumatic stress disorder (PTSD) (9.37 ± 6.74) and positive coping by inner strengths (17.63 ± 5.72). Mental fatigue was prevalent (8.15 ± 8.62), and stigma of social discrimination scored notably (23.83 ± 7.46). Quality of life was the highest in the social domain (65.38 ± 24.58). Significant correlations were observed between mental health subscales, mental fatigue, and quality of life domains. These findings highlight the critical need for targeted mental health support programs, improved social support networks, and personalized interventions to mitigate the mental health challenges faced by healthcare workers. Healthcare organizations can guarantee a resilient workforce that can handle future health crises by giving mental health resources and support systems top priority.

Relations Among Multiple Dimensions of Self-Reported Listening Effort in Response to an Auditory Psychomotor Vigilance Task.

PURPOSE: Listening effort is a broad construct, and there is no consensus on how to subdivide listening effort into dimensions. This project focuses on the subjective experience of effortful listening and tests if cognitive workload, mental fatigue, and mood are interrelated dimensions. METHOD: Two online studies tested young adults (n = 74 and n = 195) and measured subjective workload, fatigue (subscales of fatigue and energy), and mood (subscales of positive and negative mood) before and after a challenging listening task. In the listening effort task, participants responded to intermittent 1-kHz target tones in continuous white noise for approximately 12 min. RESULTS: Correlations and principal component analysis showed that fatigue and mood were distinct but interrelated constructs that weakly correlated with workload. Effortful listening provoked increased fatigue and decreased energy and positive mood yet did not influence negative mood or workload. CONCLUSIONS: The findings suggest that self-reported listening effort has multiple dimensions that can have different responses to the same effortful listening episode. The results can help guide evidence-based development of clinical listening effort tests and may reveal mechanisms for how listening effort relates to quality of life in those with hearing impairment. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.26418976.

Fatigued or bored? Investigating the effect of different types of mental fatigue on 3 km running performance.

Mental fatigue has been highly cited as having a negative impact on endurance performance. Few, however, have investigated whether different types of mental fatigue, namely active and passive fatigue, might affect endurance performance differently. This study used a repeated-measures design where 11 participants completed a 3 km run after three 32-min conditions: an actively fatiguing task (Task-load Dual-back; TloadDback); a passively fatiguing task (Mackworth Clock); and a control task (Documentary). Subjective ratings and performance on a second task (Flanker task) were taken before and after the 32-min tasks, while ratings of perceived effort, motivation and workload were taken during the 3 km run. Results showed that both fatigue conditions were mentally fatiguing, with the TloadDback rated as more demanding and the Mackworth Clock more boring and less motivating. Performance on subsequent tasks showed different effects: the TloadDback condition had the slowest responses on the post-test Flanker task, while the Mackworth Clock condition had the slowest completion time on the 3 km run, though this difference in completion times was non-significant. These results suggest that different cognitive tasks lead to different types of mental fatigue, which can lead to different outcomes on subsequent cognitive tasks but non-significant differences on subsequent physical tasks. This study highlights that to understand the influence of mental fatigue on physical performance, it is important to understand the cognitive tasks used and how different cognitive and physical tasks interact. Future work should examine whether performance outcomes in other areas commonly affected by mental fatigue, like technical and tactical sporting skills, are affected differently by active and passive fatigue.

Engagement of mental effort in response to mental fatigue: A psychophysiological analysis.

Acute mental fatigue, characterized by a transient decline in cognitive efficiency during or following prolonged cognitive tasks, can be managed through adaptive effort deployment. In response to mental fatigue, individuals can employ two main behavioral patterns: engaging a compensatory effort to limit performance decrements, or disengaging effort, leading to performance deterioration. This study investigated the behavioral pattern used by participants in mental fatigue conditions. Fifty participants underwent a sequential-task protocol with counterbalanced sessions who took place in two separate sessions: a 30-min incongruent Stroop task (fatiguing session) or a 30-min documentary viewing task (control session), followed by a time-to-exhaustion (TTE) handgrip task at 13 % of maximal voluntary contraction. Psychophysiological measures included the preejection period, heart rate variability, blood pressure, and respiration. Behavioral results showed deteriorated TTE handgrip performance after the Stroop task compared to after the documentary viewing task. During the Stroop task participants were more conservative and prioritized accuracy over speed. Self-reported fatigue was greater after the Stroop task. Psychophysiological data revealed a gradual decrease in sympathetic activity over time in both tasks, with the Stroop task showing a more pronounced decrease. Taken together, these findings suggest a disengagement of effort for a large proportion of participants (49 %) that could be partly attributed to a habituation to the demands of the Stroop task. This study illustrates the interplay of behavioral patterns of effort investment in the context of mental fatigue and underscores the role of disengagement as a dominant response to this phenomenon among healthy participants.

Evaluating the Stroop Test With Older Adults: Construct Validity, Short Term Test-Retest Reliability, and Sensitivity to Mental Fatigue.

We conducted two studies to evaluate the construct validity, short term test-retest reliability, and sensitivity to mental fatigue of the Stroop task when used with older adults. In Study 1, 40 participants visited our lab on two separate days. On the first visit, they took five screening scales, and we measured their height and body mass. On the second visit, they completed the Stroop task twice with a 30-minute interval between assessments. In Study 2, 15 different participants took a 30-minute Flanker/Reverse Flanker task during the interval between the two administrations of the Stroop tasks and they gave subjective ratings of their mental fatigue on the Visual Analogue Scale (VAS) prior to taking either of the Stroop tasks. In Study 1, participants showed a ceiling effect on the Stroop accuracy measure, there was strong concurrent validity for the Stroop with significant score differences between the Stroop's congruent and incongruent conditions (p < .001), and there was excellent response time reliability (ICC = 0.926) on day two when participants took the Stroop twice within a 30-minute inter-test interval. However, there were significant test-retest performance differences with respect to cognitive inhibition (p < .001). In Study 2, mental fatigue from the Flanker/Reverse Flanker test resulted in a significantly worse second Stroop performance (p = .045). We concluded that the Stroop task demonstrated strong concurrent validity and response time reliability among older adults, but it showed sensitivity to mental fatigue, and repeated administrations within the short 30-minute test-retest interval revealed that the most important Stroop measure (cognitive inhibition) was unreliable. We discuss the implications of these findings.

An online self-study mindfulness-based stress reduction course for people suffering from mental fatigue after an acquired brain injury.

OBJECTIVE: The Mindfulness-Based Stress Reduction (MBSR) program has shown promising results for people suffering from mental fatigue after an acquired brain injury. The aim was to evaluate the feasibility of a MBSR program performed as an online self-study course for this group of people. METHODS: Sixty participants who had suffered an acquired brain injury with lasting mental fatigue were randomized to an online MBSR course or to a waitlist control group. They answered self-report questionnaires before start and after the course. RESULTS: Sixteen completed the MBSR program. With the repeated ANOVA no significant difference between groups was found, although there was a significant change in time (the repetition factor). The post-hoc paired t-test indicated a significant reduction and a large-to-median effect size in mental fatigue (p = 0.003, d = 0.896), depression (p = 0.038, d = 0.569) and anxiety (p = 0.030, d = 0.598) for the MBSR group. No significant changes were found for the control group. CONCLUSION: An online self-study MBSR program for people suffering from mental fatigue after an acquired brain injury can be a feasible option for those suffering from less severe mental fatigue and emotional symptoms, while others may require a program adapted to their needs.

Visual perceptual processing is unaffected by cognitive fatigue.

Cognitive fatigue (CF) can lead to an increase in the latency of simple reaction time, although the processes involved in this delay are unknown. One potential explanation is that a longer time may be required for sensory processing of relevant stimuli. To investigate this possibility, the current study used a visual inspection time task to measure perceptual processing speed before and after a CF (math and memory) or non-fatiguing (documentary film) intervention. Subjective fatigue and simple reaction time significantly increased following the CF, but not the non-fatiguing intervention, confirming that CF was induced. Conversely, there was no effect of CF on inspection time task performance. It was therefore concluded that the speed of perceptual processing is not significantly impacted by CF, and thus is unlikely to underlie CF-related reaction time increases. Instead, increases in simple reaction time latency in CF may be due to delays in response preparation or initiation.

Counteracting mental fatigue for athletes: a systematic review of the interventions.

The deleterious effects of mental fatigue (MF) on athletes have been carefully studied in various sports, such as soccer, badminton, and swimming. Even though many researchers have sought ways to ameliorate the negative impact of MF, there is still a lack of studies that review the interventions used to counteract MF among athletes. This review aims to report the current evidence exploring the effects of interventions on MF and sport-specific performance, including sport-specific motor performance and perceptual-cognitive skills. Web of Science, Scopus, PubMed, and SPORTDicus (EBSCOhost) were combed through to find relevant publications. Additionally, the references and Google Scholar were searched for any grey literature. For the current review, we included only randomized controlled trials that involved athletes, a primary task to induce MF, interventions to counter MF with comparable protocols, and the outcomes of sport-specific motor performance and perceptual-cognitive skill. The selection criteria resulted in the inclusion of 10 articles. The manipulations of autonomous self-control exertion, person-fit, nature exposure, mindfulness, and transactional direct current stimulation showed that positive interventions counteract MF and improve sport-specific performance in different domains, including strength, speed, skill, stamina, and perceptual-cognitive skills. The selected interventions could significantly counteract MF and improve subsequent sport-specific performance. Moreover, self-regulation and attention resources showed the importance of the potential mechanisms behind the relevant interventions.

Long term sustained attention alters dynamic functional connectivity patterns.

Mental fatigue has attracted much attention from researchers as it plays a key role in performance efficiency and safety situations. Functional connectivity analysis using graph theory is an effective method for revealing changes in cognition resources influenced by mental fatigue. Previous studies have revealed that functional networks are dynamically reorganized. Therefore, it is critical to explore dynamic timescales of networks related to specific cognitive abilities. In this study, we used an open EEG dataset of twenty-one subjects recorded in a 60-minutes sustained attention task. After preprocessing, we constructed connectivity matrices using the weighted phase lag index (wPLI) in the theta band and characterized them with dynamic graph measures, namely characteristic path length (CPL) and clustering coefficient (CC). The results show that the frontal-parietal brain networks in theta band are involved in a sustaining attention task. When averaging from temporal and spatial activations, CPL and CC decreased with time-on-task. Our results indicate that mental fatigue results in deteriorations in sustaining attention, and graph theory analysis can provide support for mental fatigue analysis.Clinical Relevance- Identification of the effects of long term sustained attention on dynamic brain networks may be potential for mechanism study and detection of mental states and attentional deficits caused by mental diseases.

Mental fatigue, cognitive performance and autonomic response following sustained mental activity in clinical burnout.

OBJECTIVE: To investigate the effects of sustained mental activity on perceptions of mental fatigue, cognitive performance, and autonomic response in patients with clinical burnout as compared to a healthy control group. METHODS: Patients with clinical burnout (n = 30) and healthy control participants (n = 30) completed a 3-hour test session, in which they were administered a set of cognitive tests before and after an effortful cognitive task with concurrent sound exposure. Perceptions of mental fatigue and task demands (mental effort and concentration difficulties) were assessed repeatedly over the course of the test session. Heart rate variability was recorded to index autonomic response. RESULTS: In comparison with controls, perceived mental fatigue increased earlier in the session for the clinical burnout group and did not recover following a short rest period. Throughout the session, patients rated the tasks as more demanding and showed less improvement on measures of attention and processing speed, inhibition and working memory. While autonomic responses were initially comparable, there was a unique decrease in high-frequency heart rate variability in the clinical burnout group after extended testing and exposure. CONCLUSION: Patients with clinical burnout are affected differently than healthy controls by sustained mental activity, as reflected by ratings of perceived mental fatigue, aspects of cognitive performance and autonomic response. Further investigation into the role of autonomic regulation in relation to cognitive symptoms in clinical burnout is warranted.

Work performance in industry: The impact of mental fatigue and a passive back exoskeleton on work efficiency.

Mental fatigue (MF) is likely to occur in the industrial working population. However, the link between MF and industrial work performance has not been investigated, nor how this interacts with a passive lower back exoskeleton used during industrial work. Therefore, to elucidate its potential effect(s), this study investigated the accuracy of work performance and movement duration through a dual task paradigm and compared results between mentally fatigued volunteers and controls, with and without the exoskeleton. No main effects of MF and the exoskeleton were found. However, when mentally fatigued and wearing the exoskeleton, movement duration significantly increased compared to the baseline condition (ßMF:Exo = 0.17, p = .02, ω2 = .03), suggesting an important interaction between the exoskeleton and one's psychobiological state. Importantly, presented data indicate a negative effect on production efficiency through increased performance time. Further research into the cognitive aspects of industrial work performance and human-exoskeleton interaction is therefore warranted.

Ingestion of taxifolin-rich foods affects brain activity, mental fatigue, and the whole blood transcriptome in healthy young adults: a randomized, double-blind, placebo-controlled, crossover study.

The antioxidant properties of polyphenols, which are found in most plants, have been shown to be useful for maintaining health, including enhancing brain function and alleviating stress. We aimed to investigate the effect of a single intake of taxifolin-containing foods on cognitive task performance and whole blood gene expression in healthy young adults. This study was a randomized, placebo-controlled, double-blind, crossover trial in which healthy young adults were administered a single dose of either a placebo or food containing taxifolin. Cognitive tests (serial 3s, serial 7s, and rapid visual information processing) to examine brain activity and visual analog scale questionnaires to analyze mental fatigue were applied. The set of tests was repeated four times. The findings showed that taxifolin intake improved calculation abilities and reduced mental fatigue. An analysis of whole blood gene expression before and after the test revealed that the expression of foreign substance removal-related genes increased following the ingestion of taxifolin and that most differentially expressed genes were enriched in granulocytes. Taxifolin intake was shown to affect the brain activity of healthy young adults and demonstrated an antifatigue effect, thereby reducing subjective fatigue. A single intake of taxifolin may enhance the removal of foreign substances by strengthening the innate immune system and suppressing the occurrence of injury.

Quick coherence technique facilitating commercial pilots' psychophysiological resilience to the impact of COVID-19.

This study investigates the effect of quick coherence technique (QCT) on commercial pilots' resilience to the unprecedented impact of a pandemic. Eighteen commercial pilots voluntarily participated in a 2-day training course on QCT followed by 2 months of self-regulated QCT practicing during controlled rest in the flight deck and day-to day life. There are subjective and objective assessments to evaluate the effects of QCT on commercial pilots' psychophysiological resilience. Results demonstrated that QCT training can significantly increase pilots' psychophysiological resilience thereby improving their mental/physical health, cognitive functions, emotional stability and wellness on both subjective (PSS & AWSA) and objective measures (coherence scores). Moreover, pilots who continued practicing self-regulated QCT gained the maximum benefits. Current research has identified great potential to enhance pilots' mental/physical health via QCT training. Operators can develop peer support programs for pilots to increase resilience and maintain mental and physical health using the QCT technique. Practitioner summary: QCT breathing has been proven to increase commercial pilots' resilience by moderating psychophysiological coherence, strengthening mental/physical capacity and sustaining positive emotions to deal with the challenges both on the flight deck and in everyday life.HIGHLIGHTSPilots have suffered from the impact of the Covid-19 pandemic across many factors including social, economic, mental, physical, emotional, and operational issuesBiofeedback training can increase commercial pilots' resilience by moderating psychophysiological coherence, strengthening mental and physical capacitySelf-regulated practicing QCT to form a habitual behaviour is required to sustain the maximum benefits either in the flight or day-to-day lifeQCT is an effective intervention for aviation authorities and airline operators to develop peer support programs to increase pilots' fatigue resilience.

Quantitative and qualitative workload assessment in steep terrain forest operations: fostering a safer work environment through yarder automation.

Many forestry roles have changed from being manual tasks with a high physical workload to being a machine operator task with a high mental workload. Automation can support a decrease in mental fatigue by removing tasks that are repetitive and monotonous for the operators. Cable yarding presents an ideal opportunity for early adoption of automation technology; specifically the carriage movement along a defined corridor. A Valentini V-850 cable yarder was used in an Italian harvesting setting, in order to gauge the ergonomic benefit of carriage control automation. The study showed that automating yarder carriage movements improved the ergonomic situation of the workers directly involved in the related primary tasks. However, the caveat is that improving one work task may negatively affect the other work tasks, and therefore introducing automation to a worksite must be done after considering all impacts on the whole system. Practitioner summary: Automation decreased the winch operator's mental workload while improving overall productivity. At the same time, the mental and physiological workload of the operator tasked with bucking were slightly increased. Ideally, winch automation should be coupled with bucking mechanisation to balance the intervention and boost both operator well-being and productivity.

Effects of Mental Fatigue on Reaction Time in Sportsmen.

AIM: Mental fatigue (MF) has been defined as a psychobiological state commonly caused by prolonged periods of demanding cognitive activity. However, the differences between women and men in their reaction times (RTs) to visual stimuli due to mental fatigue remain largely unknown. We compare the differences in RT and heart rate after an acute intervention of mental fatigue between male and female athletes. MATERIALS AND METHODS: For this aim, 64 participants (age 31.7 ± 6.2 y) performed a routine of 15 min of the Stroop test (PsyTool), with 600 tasks and five different colors. Their heart rate (HR) was registered before, during, and one, three, and five minutes after the Stroop test. Meanwhile, the RT was evaluated before and after the Stroop test. A general linear mixed model (GLMM) and a Bonferroni post hoc test were used to compare the HR between the conditions and an ANOVA two-way analysis was used to compare the values pre-/post-Stroop test. (α = 0.05). RESULTS: The GLMM for HR showed an effect on the time (p < 0.001) and the time × group interaction (p = 0.004). The RT was significantly increased pre- to post-Stroop test (p < 0.05); however, there was no difference between the pre- and post-HR measurements (p = 1.000) and the measurements one (p = 0.559), three (p = 1.000) and five (p = 1.000) min after the Stroop test. CONCLUSION: The present findings suggest that the parasympathetic branch of the autonomous nervous system which functions as a relaxation system tends to be activated under increasing mental fatigue, with a decreased performance (RT) similarly in men and women. Therefore, athletes could use MF induced during training to improve the time delay related to motor tasks.

Ketone Ester Supplementation Improves Some Aspects of Cognitive Function during a Simulated Soccer Match after Induced Mental Fatigue.

Ketone supplementation has been proposed to enhance cognition during exercise. To assess whether any benefits are due to reduced cognitive fatigue during the latter portions of typical sport game action, we induced cognitive fatigue, provided a ketone monoester supplement (KME) vs. a non-caloric placebo (PLAC), and assessed cognitive performance during a simulated soccer match (SSM). In a double-blind, balanced, crossover design, nine recreationally active men (174.3 ± 4.2 cm, 76.6 ± 7.4 kg, 30 ± 3 y, 14.2 ± 5.5 % body fat, V˙O2 max = 55 ± 5 mL·kg BM−1·min−1; mean ± SD) completed a 45-min SSM (3 blocks of intermittent, variable intensity exercise) consuming either KME (25 g) or PLAC, after a 40-min mental fatiguing task. Cognitive function (Stroop and Choice Reaction Task [CRT]) and blood metabolites were measured throughout the match. KME reduced concentrations of both blood glucose (block 2: 4.6 vs. 5.2 mM, p = 0.02; block 3: 4.7 vs. 5.3 mM, p = 0.01) and blood lactate (block 1: 4.7 vs. 5.4 mM, p = 0.05; block 2: 4.9 vs. 5.9 mM, p = 0.01) during the SSM vs. PLAC, perhaps indicating a CHO sparing effect. Both treatments resulted in impaired CRT performance during the SSM relative to baseline, but KME displayed a reduced (p < 0.05) performance decrease compared to PLAC (1.3 vs. 3.4% reduction in correct answers, p = 0.02). No other differences in cognitive function were seen. These data suggest that KME supplementation attenuated decrements in CRT during repeated, high intensity, intermittent exercise. More study is warranted to assess fully the potential cognitive/physical benefits of KME for athletes.

Mental Fatigue Effects on the Produced Perception of Effort and Its Impact on Subsequent Physical Performances.

The purpose of this study was to investigate the relationship between mental fatigue induced by a demanding cognitive task and impaired physical performance in endurance due to a higher perception of effort. A total of 12 healthy adults and volunteers, who had previously practiced endurance activities for 4 to 8 h per week, performed a one-hour cognitive task involving either the process of response inhibition (Stroop task) or not (visualization of a documentary as control task), then 20 min of pedaling on a cycle ergometer at a constant perception of effort while cardio-respiratory and neuromuscular functions were measured. The Stroop task induces subjective feelings of mental fatigue (vigor: 3.92 ± 2.61; subjective workload: 58.61 ± 14.57) compared to the control task (vigor: 5.67 ± 3.26; p = 0.04; subjective workload: 32.5 ± 10.1; p = 0.005). This fatigue did not act on the produced perceived effort, self-imposed, and did not affect the cardio-respiratory or neuromuscular functions during the subsequent physical task whose type was medium-term endurance. Regardless of the mental condition, the intensity of physical effort is better controlled when the participants in physical activity control their perception of effort. Mental fatigue does not affect subsequent physical performance but estimated perceived exertion, which increases with the intensity and duration of the exercise.

Do Cognitive, Physical, and Combined Tasks Induce Similar Levels of Mental Fatigue? Testing the Effects of Different Moderating Variables.

Experts have highlighted the importance of coaches knowing the level of mental fatigue (MF) induced by different tasks. This study aimed to compare the mentally fatiguing nature of cognitive, physical, and combined tasks and, additionally, assess the effect of different moderating variables on MF. Twenty-three physically active (16 males: Mage = 24 years; seven females: Mage = 22.57 years) participants performed three experimental sessions: (a) physically fatiguing: 30 min of cycloergometer work (at 65%-75% of maximum heart rate), (b) mentally fatiguing: 30 min of an incongruent Stroop task, and (c) mixed fatiguing: 30 min of combining the physically and mentally fatiguing protocols. Subjective MF (visual analog scale), reaction time (psychomotor vigilance task), and cognitive performance (Stroop) were measured throughout the different protocols. Results showed significant increments in subjective MF after all tasks, with the mental and mixed protocols showing significantly higher increases. Only the mentally fatiguing protocol caused significant impairments in reaction time. No significant effects of sex, years of experience, or degree of mental toughness were observed. These results suggest that the use of all these tasks, and especially the mentally fatiguing exercises, should be avoided immediately prior to competitions due to the negative consequences of MF on performance. Moreover, this effect seems to be independent of the sex, years of experience, or mental toughness of athletes.

The effects of mental fatigue on effort allocation: Modeling and estimation.

Mental fatigue is usually accompanied by drops in task performance and reduced willingness for further exertion. A value-based theoretical account may help to explain such negative effects. In this view, mental fatigue influences perceived costs and rewards of exerting effort. However, no formal mathematical framework has yet been proposed to model and quantitatively estimate the effects of mental fatigue on subjective evaluations of effort expenditure, under possibly imperfect self-perceptions of internal fatigue states. We proposed a mathematical framework to model human cognitive effort allocations, assuming mental fatigue states are partially observable with semi-Markov dynamics. We modeled effort allocation decisions as a means to the goal of maximizing cumulative subjective values over a given time horizon. We developed an estimation method to identify subjective values and the hidden dynamics of mental fatigue, which can in future work be applied to self-reports, psychophysiological indices, and behavioral outcomes associated with fatigue. The modeling and estimation method was tested using a simulated n-back task under a free-choice paradigm, with model parameters fine-tuned from past studies. The proposed approach was able to recapitulate task performance and task engagement patterns observed under mental fatigue. This work advances a reward/cost trade-off account for explaining the exertion of mental effort and suggests new avenues for both theoretically and empirically relevant understandings of how cognitive operations are affected by mental fatigue. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Dynamic Reorganization of Functional Connectivity During Post-Break Task Reengagement.

Because of the undesired fatigue-related consequences, accumulating efforts have been made to find an effective intervention to alleviate the suboptimal cognitive function caused by mental fatigue. Nonetheless, limitations of intervention and evaluation methods may hinder the revealing of underlying neural mechanisms of fatigue recovery. Through the newly-developed dynamic functional connectivity (FC) analysis framework, this study aims to investigate the effects of two types of mid-task interventions (i.e., rest-break and moderate-intensity exercise-break) on the dynamic reorganization of FC during the execution of psychomotor vigilance test (PVT). Using a sliding window approach, temporal brain networks within each frequency band (i.e., δ , θ , α , & ß ) were estimated before and immediately after the intervention, and towards the end of the task to investigate the immediate and delayed effects respectively during post-break task reengagement. Behaviourally, similar beneficial effects of exercise- and rest-break on performance were observed, manifested by the immediate improvements after both interventions and a long-lasting influence towards the end of tasks. Moreover, temporal brain networks assessment showed significant immediate decreases of fluctuability, which was followed by an increase of fluctuability towards the end of intervention tasks. Furthermore, the temporal nodal measure revealed the channels with significant differences across tasks were mainly resided in the fronto-parietal areas that exhibited interesting frequency-dependent distribution. The observations of immediate and delayed dynamic FC reorganizations extend previous fatigue-related intervention and static FC studies, and provide new insight into the dynamic characteristics of FC during post-break task reengagement.