Change in heart rate variability with increasing time-on-task as a marker for mental fatigue: A systematic review.

Fatigue-specific changes in the autonomic nervous system are often assumed to underlie the development of mental fatigue caused by prolonged cognitive tasks (i.e. Time-on-Task). Therefore, several previous studies have chosen to investigate the Time-on-Task related changes in heart rate variability (HRV). However, previous studies have used many different HRV indices, and their results often show inconsistencies. The present study, therefore, systematically reviewed previous empirical HRV studies with healthy individuals and in which mental fatigue is induced by prolonged cognitive tasks. Articles relevant to the objectives were systematically searched and selected by applying the PRISMA guidelines. We screened 360 records found on 4 databases and found that 19 studies were eligible for full review in accordance with the inclusion criteria. In general, all studies reviewed (with the exception of two studies) found significant changes in HRV with increasing Time-on-Task, suggesting that HRV is a reliable autonomic marker for Time-on-Task induced fatigue. The most conclusive HRV indices that showed a consistent Time-on-Task effect were the low frequency component of HRV and the time domain indices, particularly the root mean square of successive differences. Time-on-Task typically induced an increasing trend in both type of measures.

Correction: Enhanced cardiac vagal tone in mental fatigue: Analysis of heart rate variability in Time-on-Task, recovery, and reactivity.

[This corrects the article DOI: 10.1371/journal.pone.0238670.].

Structural neural correlates of mental fatigue and reward-induced improvement in performance.

Neuroimaging studies investigating the association between mental fatigue (henceforth fatigue) and brain physiology have identified many brain regions that may underly the cognitive changes induced by fatigue. These studies focused on the functional changes and functional connectivity of the brain relating to fatigue. The structural correlates of fatigue, however, have received little attention. To fill this gap, this study explored the associations of fatigue with cortical thickness of frontal and parietal regions. In addition, we aimed to explore the associations between reward-induced improvement in performance and neuroanatomical markers in fatigued individuals. Thirty-nine healthy volunteers performed the psychomotor vigilance task for 15 min (i.e., 3 time-on-task blocks of 5 min) out of scanner; followed by an additional rewarded block of the task lasting 5 min. Baseline high-resolution T1-weigthed MR images were obtained. Reaction time increased with time-on-task but got faster again in the rewarded block. Participants' subjective fatigue increased during task performance. In addition, we found that higher increase in subjective mental fatigue was associated with the cortical thickness of the following areas: bilateral precuneus, right precentral gyrus; right pars triangularis and left superior frontal gyrus. Our results suggest that individual differences in subjective mental fatigue may be explained by differences in the degree of cortical thickness of areas that are associated with motor processes, executive functions, intrinsic alertness and are parts of the default mode network.

The interference of negative emotional stimuli on semantic vigilance performance in a dual-task setting.

A large body of previous research has shown that emotional stimuli have an advantage in a wide variety of cognitive processes. This was mainly observed in visual search and working memory tasks. Emotionally charged objects draw and hold attention, are remembered better, and interfere more with the completion of the primary task than neutral ones. Therefore, it seems reasonable to assume that emotional stimuli also greatly affect sustained attention and vigilance decrement. In the present research, we investigated whether emotional stimuli demand more attentional resources than neutral ones in a dual-task paradigm. We adopted the abbreviated semantic discrimination vigilance task and measured participants' (N = 49) performance in a single-task and two dual-task settings. In the dual-task conditions, the visual semantic vigilance paradigm was combined with an auditory word recall task (with neutral or emotional stimuli). We found reduced vigilance and improved word recall performance in the emotional dual-task condition compared to the neutral dual-task and single-task conditions. The reduced performance was apparent throughout the task, while in the neutral conditions, participants' performance first increased and then dropped as time progressed. To conclude, our results indicate that emotional stimuli not only have an advantage in cognitive processing but also demand more attentional resources continuously while it is present compared to neutral stimuli. These results are consistent with the emotionality effect theory and evolutionary accounts of the neural circuits underlying motivated behaviors associated with critical survival needs.

What do patients think about the Hungarian health care system and medical students' learning outcomes? A cross-sectional study on the patients' perspective in Hungary.

BACKGROUND: The doctor-patient relationship has changed a lot in the 21st century and the varying expectations of the patients play an important role in future professional medical care. The knowledge of patients' needs is crucial in determining the learning outcomes in medical education. The objective of this study was to examine the expectations of the patients regarding professional and soft skills (e.g. communicational skills, empathy) of doctors and to get a deeper view. METHODS: Face-to face data collection through self-reported questionnaire in accredited health care institutions (GPs, hospitals, outpatient care) in Hungary was carried out in 2019. Descriptive statistics, independent sample t-tests, k-means cluster and gap matrices were performed to analyze the data. RESULTS: In total 1115 patients (male-female: 50-50%, age groups: between 18 and 30: 20%, between 31 and 60: 40% above 60: 40%) participated in the survey. They rated sixteen learning outcomes along with two dimensions: importance and satisfaction. Except for one learning outcome, patients rated the outcomes more important than they were satisfied with them (negative gap). Positive gap was registered only in the case of respecting individual specialty during patient care. CONCLUSIONS: The results suggest the importance of learning outcomes in relation to the rate of satisfaction from the patients' perspectives. In addition, the results support that patients' need are not met in medical care. Patients' ratings also make an emphasis on the fact that besides professional knowledge other learning outcomes are also important in health care which should have been emphasized as a basis in medical education.

The neural correlates of mental fatigue and reward processing: A task-based fMRI study.

Increasing time spent on the task (i.e., the time-on-task (ToT) effect) often results in mental fatigue. Typical effects of ToT are decreasing levels of task-related motivation and the deterioration of cognitive performance. However, a massive body of research indicates that the detrimental effects can be reversed by extrinsic motivators, for example, providing rewards to fatigued participants. Although several attempts have been made to identify brain areas involved in mental fatigue and related reward processing, the neural correlates are still less understood. In this study, we used the psychomotor vigilance task to induce mental fatigue and blood oxygen-level-dependent functional magnetic resonance imaging to investigate the neural correlates of the ToT effect and the reward effect (i.e., providing extra monetary reward after fatigue induction) in a healthy young sample. Our results were interpreted in a recently proposed neurocognitive framework. The activation of the right middle frontal gyrus, right insula and right anterior cingulate gyrus decreased as fatigue emerged and the cognitive performance dropped. However, after providing an extra reward, the cognitive performance, as well as activation of these areas, increased. Moreover, the activation levels of all of the mentioned areas were negatively associated with reaction times. Our results confirm that the middle frontal gyrus, insula and anterior cingulate cortex play crucial roles in cost-benefit evaluations, a potential background mechanism underlying fatigue, as suggested by the neurocognitive framework.

Generalisable machine learning models trained on heart rate variability data to predict mental fatigue.

A prolonged period of cognitive performance often leads to mental fatigue, a psychobiological state that increases the risk of injury and accidents. Previous studies have trained machine learning algorithms on Heart Rate Variability (HRV) data to detect fatigue in order to prevent its consequences. However, the results of these studies cannot be generalised because of various methodological issues including the use of only one type of cognitive task to induce fatigue which makes any predictions task-specific. In this study, we combined the datasets of three experiments each of which applied different cognitive tasks for fatigue induction and trained algorithms that detect fatigue and predict its severity. We also tested different time window lengths and compared algorithms trained on resting and task related data. We found that classification performance was best when the support vector classifier was trained on task related HRV calculated for a 5-min time window (AUC = 0.843, accuracy = 0.761). For the prediction of fatigue severity, CatBoost regression showed the best performance when trained on 3-min HRV data and self-reported measures (R2 = 0.248, RMSE = 17.058). These results indicate that both the detection and prediction of fatigue based on HRV are effective when machine learning models are trained on heterogeneous, multi-task datasets.

Examining the mental health adversity among healthcare providers during the two waves of the COVID-19 pandemic: results from a cross-sectional, survey-based study.

OBJECTIVES: The current global health crisis of the COVID-19 pandemic has drastically affected the whole population, but healthcare workers are particularly exposed to high levels of physical and mental stress. This enormous burden requires both the continuous monitoring of their health conditions and research into various protective factors. DESIGN: Cross-sectional surveys. SETTING AND PARTICIPANTS: Self-administered questionnaires were constructed assessing COVID-19-related worries of health workers in Hungary. The surveys were conducted during two consecutive waves of the COVID-19 pandemic (N-first wave=376, N-second wave=406), between 17 July 2020 and 31 December 2020. PRIMARY AND SECONDARY OUTCOME MEASURES: COVID-19-related worry, well-being and distress levels of healthcare workers. We also tested whether psychological resilience mediates the association of worry with well-being and distress. Multiple linear regression analyses were performed. RESULTS: The results indicated that healthcare workers had high levels of worry and distress in both pandemic waves. When comparing the two waves, enhanced levels of worry (Wald's χ2=4.36, p=0.04) and distress (Wald's χ2=25.18, p<0.001), as well as compromised well-being (Wald's χ2=58.64, p<0.001), were found in the second wave. However, not all types of worries worsened to the same extent across the waves drawing attention to some specific COVID-19-sensitive concerns. Finally, the protective role of psychological resilience was shown by a mediator analysis suggesting the importance of increasing resilience as a key factor in maintaining the mental health of healthcare workers in the burden of the COVID-19 pandemic. CONCLUSIONS: Our results render the need for regular psychological surveillance in healthcare workers. REGISTRATION: Hungarian Scientific and Research Ethics Committee of the Medical Research Council (IV/5079-2/2020/EKU).

Pain catastrophizing, pain sensitivity and fear of pain are associated with early life environmental unpredictability: a path model approach.

BACKGROUND: Socioeconomic disadvantages in the childhood environment might strongly influence beliefs and behavior characterizing the adult years. When children experience unpredictable and adverse situations, they develop an unpredictability schema with the core belief that situations are unpredictable. METHODS: In two studies, we examined the association of childhood socioeconomic disadvantages with self-reported pain sensitivity, pain catastrophizing, and pain-related fear. Multidimensional survey measures were used to assess environmental conditions experienced in childhood. In addition, participants completed the Pain Catastrophizing Scale, Pain Sensitivity Questionnaire, Body Awareness Questionnaire, Unpredictability Schema Questionnaire, and Fear of Pain Questionnaire. In Study 1 (N = 252), in separate models, we examined pain sensitivity and pain catastrophizing of a community sample of pain-free young individuals in association with their childhood experiences. In Study 2 (N = 293), in a new sample, but with a wider age range, we examined the association of early life socioeconomic disadvantages with pain-related fear. In both studies, the predictions were tested with Structural Equation Modeling. Our models constituted a path from childhood socioeconomic status and household unpredictability to pain variables via the factors of family resources, unpredictability schemas, and body awareness. RESULTS AND CONCLUSIONS: The findings converged on the conclusion that individuals experiencing disadvantageous early life conditions tended to have an elevated level of pain catastrophizing, higher perceived sensitivity to pain, and higher level of pain-related fear. These associations were mediated by an unpredictability schema and body awareness.

Negative time perspective predicts the self-perceived affective and physical components of pain independently from depression, anxiety, and early life circumstances.

People's attitudes toward time, the time perspectives (TPs) rooted in past experiences, might be crucial for the emotional evaluation of life events, such as painful situations. In a survey-based study (N = 353), we investigated the relationship of TPs with the self-perceived affective and physical aspects of pain. Specifically, we hypothesised that past-negative TP would be associated with a negative emotional appraisal of pain characterised by higher pain-related catastrophizing, fear, and physical sensitivity to pain. We tested this hypothesis with hierarchical regression models, adding depression, anxiety, and variables of early life circumstances to the model stepwise. Early life circumstances (i.e., socioeconomic status, household unpredictability, and family resources) were measured retrospectively using questionnaires. In addition, based on the results of the regression analyses, we built a structural equation model (SEM) and tested whether past-negative mediates the effect of household unpredictability toward emotional and physical appraisal of pain. We found that individuals scoring high on past-negative TP had greater pain catastrophizing, pain-related fear, and sensitivity to pain. Further, there was evidence that these associations are independent from depression, anxiety, and early life circumstances. Finally, SEM analysis suggested that unpredictable early life circumstances were directed toward intense, negatively emotionalised pain perception via the mediation of the past-negative TP. The findings generally support the view that pain behaviour is formed by emotional states and attitudes that are linked to past experiences that are not necessarily specific to the context of pain.

Recurrent acute pancreatitis prevention by the elimination of alcohol and cigarette smoking (REAPPEAR): protocol of a randomised controlled trial and a cohort study.

BACKGROUND/OBJECTIVES: Acute recurrent pancreatitis (ARP) due to alcohol and/or tobacco abuse is a preventable disease which lowers quality of life and can lead to chronic pancreatitis. The REAPPEAR study aims to investigate whether a combined patient education and cessation programme for smoking and alcohol prevents ARP. METHODS AND ANALYSIS: The REAPPEAR study consists of an international multicentre randomised controlled trial (REAPPEAR-T) testing the efficacy of a cessation programme on alcohol and smoking and a prospective cohort study (REAPPEAR-C) assessing the effects of change in alcohol consumption and smoking (irrespective of intervention). Daily smoker patients hospitalised with alcohol-induced acute pancreatitis (AP) will be enrolled. All patients will receive a standard intervention priorly to encourage alcohol and smoking cessation. Participants will be subjected to laboratory testing, measurement of blood pressure and body mass index and will provide blood, hair and urine samples for later biomarker analysis. Addiction, motivation to change, socioeconomic status and quality of life will be evaluated with questionnaires. In the trial, patients will be randomised either to the cessation programme with 3-monthly visits or to the control group with annual visits. Participants of the cessation programme will receive a brief intervention at every visit with direct feedback on their alcohol consumption based on laboratory results. The primary endpoint will be the composite of 2-year all-cause recurrence rate of AP and/or 2-year all-cause mortality. The cost-effectiveness of the cessation programme will be evaluated. An estimated 182 participants will be enrolled per group to the REAPPEAR-T with further enrolment to the cohort. ETHICS AND DISSEMINATION: The study was approved by the Scientific and Research Ethics Committee of the Hungarian Medical Research Council (40394-10/2020/EÜIG), all local ethical approvals are in place. Results will be disseminated at conferences and in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT04647097.

Confirming the factor structure and improving the screening function of the Medical Fear Survey - short in a Hungarian community sample.

Medical Fear Survey (MFS) was designed to assess the fear of medical treatments and related factors through five dimensions including fears of injections and blood draws, sharp objects, blood, mutilation, medical examination and physical symptoms. We analysed the factor structure and validity of a short version of MFS in Hungarian, on a large sample (2631 participants; 558 men, 2067 women) focusing on possible age and gender differences (aged Mean = 30.4, SD = 13.4), which were not reported for the original version. Furthermore, using discriminant analysis, potential screening function of the MFS-short was examined. Results supported construct and convergent validity and scale-reliability for the five-factor structure of the MFS-short. Further analyses demonstrated excellent discriminatory power for four subscales, while one subscale had acceptable power. Our findings provide implications for the utility of MFS-short as a screening measure in assessing the severity of medical fears controlling for gender differences and age-biases.

Visually guided movement with increasing time-on-task: Differential effects on movement preparation and movement execution.

Top-down cognitive control seems to be sensitive to the detrimental effects of fatigue induced by time-on-task (ToT). The planning and preparation of the motor responses may be especially vulnerable to ToT. Yet, effects of ToT specific to the different phases of movements have received little attention. Therefore, in three experiments, we assessed the effect of ToT on a mouse-pointing task. In Experiment 1, there were 16 possible target positions with variable movement directions. In Experiment 2, the layout of the targets was simplified. In Experiment 3, using cuing conditions, we examined whether the effects of ToT on movement preparation and execution were caused by an increased orientation deficit or decreased phasic alertness. In each experiment, initiation of movement (preparatory phase) became slower, movement execution became faster and overall response time remained constant with increasing ToT. There was, however, no significant within-person association between the preparatory and execution phases. In Experiments 1 and 2, we found a decreasing movement time/movement error ratio, suggesting a more impulsive execution of the pointing movement. In addition, ToT was also accompanied with imprecise movement execution as indicated by the increased errors, mainly in Experiment 2. The results of Experiment 3 indicated that ToT did not induce orientation and phasic alerting deficits but rather was accompanied by decreased tonic alertness.

Enhanced cardiac vagal tone in mental fatigue: Analysis of heart rate variability in Time-on-Task, recovery, and reactivity.

Heart Rate Variability (HRV) has been suggested as a useful tool to assess fatigue-sensitive psychological operations. The present study uses a between and within-subject design with a cognitively demanding task and a documentary viewing condition, to examine the temporal profile of HRV during reactivity, Time-on-Task (ToT), and recovery. In the cognitive task group, participants worked on a bimodal 2-back task with a game-like character (the Gatekeeper task) for about 1.5 hours, followed by a 12-minute break, and a post-break block of performance (about 18 min). In the other group, participants watched documentaries. We hypothesized an increasing vagal-mediated HRV as a function of Time spent on the Gatekeeper task and no HRV change in the documentary viewing group. We also analyzed the trial-based post-response cardiac activity as a physiological associate of task-related motivation. Relative to the documentary-viewing, ToT was associated with an elevated level of subjective fatigue, decreased heart rate, and increased HRV, particularly in the vagal-mediated components. Based on fatigued participants' post-error cardiac slowing, and post-error reaction time analyses, we found no evidence for motivation deficits. The present findings suggest that the parasympathetic branch of the autonomous nervous system functioning as a relaxation system tends to be activated under increasing mental fatigue. In addition, the study shows that many HRV indices also seem to change when individuals are engaged in a prolonged, less fatiguing activity (e.g. documentary viewing). This finding emphasizes the relevance of comparisons/control conditions in ToT experiments.

Personalised health education against health damage of COVID-19 epidemic in the elderly Hungarian population (PROACTIVE-19): protocol of an adaptive randomised controlled clinical trial.

BACKGROUND: Early reports indicate that COVID-19 may require intensive care unit (ICU) admission in 5-26% and overall mortality can rise to 11% of the recognised cases, particularly affecting the elderly. There is a lack of evidence-based targeted pharmacological therapy for its prevention and treatment. We aim to compare the effects of a World Health Organization recommendation-based education and a personalised complex preventive lifestyle intervention package (based on the same WHO recommendation) on the outcomes of the COVID-19. METHODS: PROACTIVE-19 is a pragmatic, randomised controlled clinical trial with adaptive "sample size re-estimation" design. Hungarian population over the age of 60 years without confirmed COVID-19 will be approached to participate in a telephone health assessment and lifestyle counselling voluntarily. Volunteers will be randomised into two groups: (A) general health education and (B) personalised health education. Participants will go through questioning and recommendation in 5 fields: (1) mental health, (2) smoking habits, (3) physical activity, (4) dietary habits, and (5) alcohol consumption. Both groups A and B will receive the same line of questioning to assess habits concerning these topics. Assessment will be done weekly during the first month, every second week in the second month, then monthly. The composite primary endpoint will include the rate of ICU admission, hospital admission (longer than 48 h), and mortality in COVID-19-positive cases. The estimated sample size is 3788 subjects per study arm. The planned duration of the follow-up is a minimum of 1 year. DISCUSSION: These interventions may boost the body's cardiovascular and pulmonary reserve capacities, leading to improved resistance against the damage caused by COVID-19. Consequently, lifestyle changes can reduce the incidence of life-threatening conditions and attenuate the detrimental effects of the pandemic seriously affecting the older population. TRIAL REGISTRATION: The study has been approved by the Scientific and Research Ethics Committee of the Hungarian Medical Research Council (IV/2428- 2 /2020/EKU) and has been registered at clinicaltrials.gov ( NCT04321928 ) on 25 March 2020.

Disentangling the facilitating and hindering effects of threat-related stimuli - A visual search study.

Although large body of research has demonstrated the attention-grabbing nature of threat-related stimuli, threat could also facilitate attentional processes. Previous studies suggest a linear relationship between the facilitating effect of the arousal level conveyed by threat and performance on visual search tasks. Due to the temporal competition bias favouring stimuli with higher arousal level, this could be more pronounced for shorter onset times. Here, through two experiments we aimed to disentangle the two effects by using a visual search paradigm that allowed us to separate the emotional stimuli and the cognitive task. We manipulated stimulus onset time and threat intensity. Participants saw neutral and threatening pictures as priming stimuli, and then, they had to find numbers in ascending order in a matrix array. We measured the reaction time for finding the first number, and search time for finding all the numbers. Our results showed that when the priming stimulus is presented, longer threatening pictures produced longer reaction times compared to neutral ones, which was reversed with increase in arousal. We did not find any significant effects for the shorter onset time. Further theoretical and methodological implications are discussed.

Cross-Modal Conflict Increases With Time-on-Task in a Temporal Discrimination Task.

The modality appropriateness hypothesis argues that the auditory modality is preferred over the visual modality in tasks demanding temporal operations; hence, we predicted that responses to visual stimuli would be more sensitive to the detrimental effect of Time-on-Task. We used a bimodal temporal discrimination task. The factors were durational congruency between the modalities and the direction of modality-transmission. Participants needed to decide the duration of the cued stimulus (visual or auditory). The first five blocks of the task lasted about 1.5 h without rest [Time-on-Task (ToT) period]. The participants then had a 12-min break followed by an additional block of trials. Subjective fatigue, reaction time, error rates, and electrocardiographic data were recorded. In the visual modality, we found an enhanced congruency effect as a function of ToT. The cost of attentional shifting was higher in the auditory modality, but remained constant, suggesting that processing of auditory stimuli is robust against the effects of fatigue. Performance did not improve after the break, indicating that the effects of fatigue could not be overcome by taking a brief break. The heart rate variability (HRV) data showed that vagal inhibition increased with ToT, but this increase was not associated with the changes in performance.

Does Threat Have an Advantage After All? - Proposing a Novel Experimental Design to Investigate the Advantages of Threat-Relevant Cues in Visual Processing.

The automatic visual attentional procession of threatening stimuli over non-threatening cues has long been a question. The so-called classical visual search task (VST) has quickly become the go-to paradigm to investigate this. However, the latest results showed that the confounding results could originate from the shortcomings of the VST. Thus, here we propose a novel approach to the behavioral testing of the threat superiority effect. We conducted two experiments using evolutionary relevant and modern real-life scenes (e.g., forest or street, respectively) as a background to improve ecological validity. Participants had to find different targets in different spatial positions (close to fovea or periphery) using a touch-screen monitor. In Experiment 1 participants had to find the two most often used exemplar of the evolutionary and modern threatening categories (snake and gun, respectively), or neutral objects of the same category. In Experiment 2 we used more exemplars of each category. All images used were controlled for possible confounding low-level visual features such as contrast, frequency, brightness, and image complexity. In Experiment 1, threatening targets were found faster compared to neutral cues irrespective of the evolutionary relevance. However, in Experiment 2, we did not find an advantage for threatening targets over neutral ones. In contrast, the type of background, and spatial position of the target only affected the detection of neutral targets. Our results might indicate that some stimuli indeed have an advantage in visual processing, however, they are not highlighted based on evolutionary relevance of negative valence alone, but rather through different associational mechanisms.

Examining the Deviation From Balanced Time Perspective in the Dark Triad Throughout Adulthood.

Individuals who score high on Dark Triad (DT) personality traits (i.e., Machiavellianism, subclinical narcissism and subclinical psychopathy) have been found to prefer a fast life strategy with enhanced motivation for immediate resource acquisition and short-term benefits. In line with these points, recent studies have found evidence showing that DT traits are associated with a biased, strongly present-oriented time perspective. In the current study, we aimed to examine whether the temporal attitude of individuals high in DT is deviant from a balanced time perspective (BTP) to a significant extent. To achieve this aim, we applied two operationalizations published in earlier studies to quantify BTP: the Deviation from Balanced Time Perspective coefficient (DBTP), calculated as the difference between individuals' time perception and the optimal time perspective, as well as the person-oriented approach of identifying groups of individuals with similar time perception. Importantly, the age of participants (N = 346) covered a long and continuous period of adulthood-from the young adulthood to the elderly-in order to examine the moderating effect of age on the association of DT and BTP. Machiavellianism and psychopathy were both found to be clearly deviant from a BTP. In contrast, higher scores on narcissism were positively associated with a BTP profile. The DBTP analysis, however, suggested that this beneficial effect of narcissism was only prevalent among the elderly individuals.