Evaluation of mental fatigue based on multipsychophysiological parameters and kernel learning algorithms

Autonomic function classification and sleep quality among young adults in Central Java, Indonesia: A cluster analysis.

The present study evaluated the relationship between acute chest syndrome (ACS) and autonomic nervous system (ANS) activity in patients with hemoglobin SS disease (Hb SS). Nine patients had suffered ACS were matched by age and gender to patients who had not suffered ACS and ANS activity, pulmonary function and history of painful crisis were compared. Correlations between number of episodes of ACS suffered and these variables were determined. The results demonstrated that 1) patients with a history of ACS ever had lower parasympathetic nervous system (PNS) activity and lower global ANS activity than patients with no ACS ever (p < 0.05), 2) the number of ACS episodes ever negatively correlated (p < 0.05) with PNS activity and global ANS activity and 3) There were no significant associations between lung function or a history of painful crisis in these patients. In conclusion, a history of ACS was associated with ANS dysfunction in adults with Hb SS disease.

AUTONOMIC AND HEMODYNAMIC ACTIVITY IN SEPSIS

Several cardiovascular disease (CVD) risk factors (e.g., hypertension, poor glycemic control) can affect and be affected by autonomic nervous system (ANS) activity. Since excess adiposity can influence CVD development through its effect on hypertension and diabetes mellitus, it is important to determine how adiposity and altered ANS activity are related. The present study employed structural equation modeling to investigate the relation between adiposity and ANS activity both directly and indirectly through biological variables typically associated with glycemic impairment and cardiac stress in older adults. Utilizing the Atherosclerosis Risk in Communities (ARIC) dataset, 1,145 non-smoking adults (74±4.8 yrs, 62.8% female) free from known CVD, hypertension, and diabetes and not currently taking beta-blockers were evaluated for fasting blood glucose (FBG), insulin, and HbA1c concentrations, waist circumference (WC), blood pressure (BP), and markers of ANS activity. WC was recorded just above the iliac crest and was used to reflect central adiposity. Resting 2-minute electrocardiograph recordings, pulse wave velocity, and ankle-brachial index data were used to assess the root mean square of successive differences in RR intervals (RMSSD) and the pre-ejection period (PEP), markers of parasympathetic and sympathetic activity, respectively. FBG, insulin, and HbA1c inferred a latent variable termed glycemic impairment (GI), whereas heart rate and diastolic BP inferred a latent variable termed cardiac stress (CS). The structural equation model fit was acceptable [root mean square error of approximation = 0.050 (90% CI = .036, .066), comparative fit index = .970, Tucker Lewis Index = 0.929], with adiposity having both significant direct (β = 0.208, p = 0.018) and indirect (β = -.217, p = .041) effects on PEP through GI. Adiposity displayed no significant direct effect on RMSSD. CS displayed a significant pathway (β = -0.524, p = 0.035) on RMSSD, but the indirect effect of WC on RMSSD through CS did not reach statistical significance (β = -0.094, p = 0.137). These results suggest that adiposity's relation to ANS activity is multifaceted, as increased central adiposity had opposing direct and indirect effects on markers of sympathetic activity in this population of older adults.

The objective was to study changes in EEG time-domain Kolmogorov complexity under different mental fatigue state and to evaluate mental fatigue using Lempel-Ziv complexity analysis of spontaneous EEG in healthy human subjects. EEG data for healthy subjects were acquired using a net of 2 electrodes (Fp1 and Fp2) at PM 4:00, AM 12:00 and AM 3:00 in the 24 hours sleep-deprived mental fatigue experiments. It was presented that initial results for eight subjects examined in three different mental fa-tigue state with 2-channel EEG time-domain Lempel-Ziv complexity computations. It was found that the value of mean Lempel-Ziv com-plexity corresponding to a special mental state fluctuates within the special range and the value of C(n) increases with mental fatigue increasing for the total frequency spectrum. The result in-dicates that the value of C(n) is strongly cor-relative with the mental fatigue state. These re-sults suggest that it may be possible to nonin-vasively differentiate different mental fatigue level according to the value of C(n) for particular mental state from scalp spontaneous EEG data. This method may be useful in further research and efforts to evaluate mental fatigue level ob-jectively. It may also provide a basis for the study of effects of mental fatigue on central neural system.

Work-related muscular fatigue is a common problem among office computer users. The purpose of this study was to examine shoulder and arm muscular fatigue induced during visual display terminal (VDT) keyboard use tasks. Electromyography signals were recorded from the right side upper trapezius, deltoid and extensors of the wrist/fingers during VDT task and during isometric contractions task respectively. Mean Power Frequency (MPF) and Root Mean Square value (RMS) were computed and used to evaluate the changes of EMG signal of all measured muscles. The results showed that MPF decrease and RMS increase with time during every isometric contraction experimental blocks for all measured muscles. However, RMS and MPF did not showed obvious trend with time throughout VDT experimental task and throughout isometric contraction experimental task, it is means that MPF and RMS obtained during isometric contraction are not sensitive parameters of muscle fatigue. These results are helpful for finding effective objective assessment method that can identify office VDT workers who are at risk to develop chronic neck, shoulder and arm complaints.

Autonomic nervous system activity in premature and full-term infants from theoretical term to 7 years

Physiology of brain death is characterized by major disturbances of autonomic nervous system (ANS) activity which can lead to graft dysfunction. These findings exhibit the importance of early diagnosis of brain death to improve transplantation outcome. The aim of this prospective study was to assess whether heart rate variability (HRV) analysis, a noninvasive method to investigate ANS activity in comatose patients, could achieve this goal. A total of 14 brain-injured patients were included in the study as soon as they exhibited the clinical signs of imminent brain death. The electrocardiogram was then recorded from two leads with a Holter digital monitor. The clinical diagnosis of brain death was considered after an autonomic storm had occurred. HRV was assessed from 6 h before to 6 h after brain death in both time domain and spectral analysis, estimating either global ANS activity (index of variability, total power), parasympathetic activity (percentage of delta of R-R interval >50 ms, root mean square for successive interval differences, LnHF) or sympathetic activity (LnLF). Hourly averages of these variables were compared by using one-way analysis of variance. To assess whether HRV could per se diagnose brain death, receiver operating characteristic curves were generated for total power, root mean square for successive interval differences, and LnHF. We observed, for 6 h before brain death, a progressive extinction of the influence of the ANS on cardiovascular regulation. There was no activity in the two components of the ANS as soon as brain death occurred. HRV analysis appeared to be a very sensitive but a less specific method of diagnosing brain death. A total of 14 brain-injured patients with the clinical criteria of imminent brain death were enrolled for electrocardiogram recording and heart rate variability analysis (a noninvasive method to investigate autonomic nervous system activity). For 6 h before brain death, we observed a progressive extinction of autonomic nervous system activity which was not present as soon as brain death was clinically evoked.

Introduction: Fatigue is a gradual and cumulative process. This mindset is related to the lack of motivation to make any effort, as well as decreased efficiency, attentiveness, and, eventually, malfunction. Aim: The present study aims to investigate how mental and muscle fatigue affects spatial working memory. Method: The research method was quasi-experimental and was performed using the pretestposttest design. The participants in this study were 20 to 30 year old male students of Shahid Beheshti University of Tehran in 2021, of whom, 14 subjects were selected by convincing method as the sample using the G-Power approach and previous investigations. The Mental Fatigue Self-Assessment Scale, Corsi Block software, Stroop software, and the Monark Bike Ergometer were utilized. In addition, the repeated measurement analysis of variance test in SPSS-23 was used to analyze the data. Results: The results indicated that mental fatigue condition had a significant effect on working memory (P=0.002); and has reduced the efficiency of working memory. But muscle fatigue conditions had no significant effect on assessing working memory, and in these conditions there was a better performance in working memory (P=0.065). Conclusion: The findings of this study emphasize the importance of mental fatigue in reducing working memory performance, even though this type of fatigue is related to cognitive and cerebral functioning. Accordingly, the findings are in line with a top-down approach, as well as cognitive perspectives such as generalized motor program theory.

AUTONOMIC NERVOUS SYSTEM OVERACTIVITY IN MEN WITH LOWER URINARY TRACT SYMPTOMS SECONDARY TO BENIGN PROSTATIC HYPERPLASIA

Introduction: Vigorous physical exertion, such as a marathon, evokes long lasting changes in the autonomic cardiac regulation and peripheral fatigue. Aim of the study: We investigated changes in the autonomic nervous system (ANS) activity simultaneously with the subjective feeling of fatigue from the 67 hours following a race (42.195 km) in 31-year-old male amateur athlete. Methods: The ANS activity was assessed by spectral analysis of heart rate variability (SA HRV) during orto-clinostatics maneuvers. Both frequency-domain measures and age-dependent complex indexes of the SA HRV were used. Post-race ANS activity was assessed at the beginning of the 7 th , the 19 th , the 34 th , the 44 th , the 58 th , and the 67 th hour of the recovery period. Results: At the 19 th hour after the race, the overall spectral power had risen above the initial level, primarily owing to the prevailing sympathetic activity over the increasing vagal activity. By the 44 th hour, a further significant increase in ANS activity had occurred, this time due to the overriding vagal activity. A high level of subjectively perceived fatigue persisted throughout the entire recovery period monitored. Conclusion: This work demonstrated that the ANS activity was completely restored by the 44 th hour of post-marathon recovery. The high level of subjectively perceived fatigue persisted throughout the entire recovery period monitored and was not correlated to the ANS activity.

In this study we evaluated, in 10 sevoflurane-anesthetized pigs undergoing abdominal surgery, different techniques for measuring autonomic nervous system (ANS) activity: ANSiscope index, spectral analysis of heart-rate variability, hemodynamic variables, and plasma catecholamines and cortisol levels. Animals underwent a 120-min anesthesia during which unilateral ovariectomy was performed. Cardiovascular and respiratory responses were monitored. ANSiscope indices (ANSindex sympathetic, ANSindex parasympathetic and balANSindex) were used to monitor ANS activity. Spectral analysis was performed using an autoregressive model with a parametric method. The low frequency (LF) and high frequency (HF) components were used to interpret the power spectral density of short-term electrocardiograms (ECGs). The relationship LF/(LF+HF) reflects sympathetic activity, HF/(LF+HF) indicates parasympathetic activity, and the LF/HF ratio gives the predominance of the system. Plasma concentrations of adrenaline, noradrenaline, and cortisol were determined at different times. Correlation (P < 0.01) was found between the balANSindex and adrenaline levels and between LF/HF ratio and plasma adrenaline concentrations. Moreover, a significant (P < 0.01) correlation was found between the balANSindex and LF/HF ratio. However, no correlation was seen between the registered ANSiscope indices and hemodynamic variables. The correlation seen in this study suggests that the balANSindex could be a useful tool to monitor ANS activity during anesthesia and surgery.

Effects of brisk walking on autonomic nervous system reactivation in nursing home residents

To test the effects of mental fatigue (MF) on tackling technique on the dominant and nondominant shoulders in rugby union. Twenty male amateur rugby union players and a total of 953 tackles were analyzed. A randomized crossover counterbalanced design was used across a non-MF (control) and an MF condition. During each condition, each player performed 24 tackles, divided into 4 sets of 6 tackles (3 tackles on each shoulder). In the MF condition, players performed the Stroop Task between each set of tackles. A video recording of each tackle was used to evaluate each player's technical proficiency. A score of 1 point was awarded if a specific technique was performed correctly, and 0 point was given if not. The total score, measured in arbitrary units (AU) out of 11, represents the player's overall tackling proficiency. Overall, players displayed a significantly lower technical proficiency score in the MF condition compared to control (set 2: control 7.30 [7.04-7.57] AU vs MF 6.91 [6.70-7.12] AU, P = .009, effect size (ES) = 0.30 small and set 3: control 7.34 [7.11-7.57] AU vs MF 6.88 [6.66-7.11] AU, P = .002, ES = 0.37 small). For the nondominant shoulder, players had a significantly lower technical proficiency score during the MF condition at set 2 (control 7.05 [6.68-7.41] AU vs MF 6.69 [6.42-6.96] AU, P = .047, ES = 0.29 small) and set 3 (control 7.14 [6.83-7.45] AU vs MF 6.61 [6.35-6.87] AU, P = .007, ES = 0.49 small). MF can diminish a player's overall tackling proficiency, especially when tackling on the nondominant shoulder. The physiological mechanism for this finding may be impaired executive function and suboptimal functioning of neural signals and pathways, which result in less skillful coordination of movement. To further understand and explain MF-induced physiological changes in tackling, the feasibility of monitoring brain activity (such as electroencephalogram) and neuromuscular function (such as electromyogram) needs to be investigated. The findings from this study may also contribute to the development of more effective tackle training programs for injury prevention and performance.

Analysis of heart rate variability (HRV) is a recognized tool in the assessment of autonomic nervous system (ANS) activity. Indeed, both time and spectral analysis techniques enable us to obtain indexes that are related to the way the ANS regulates the heart rate. However, these techniques are limited in terms of the lack of thresholds of the numerical indexes, which is primarily due to high inter-subject variability. We proposed a new fetal HRV analysis method related to the parasympathetic activity of the ANS. The aim of this study was to evaluate the performance of our method compared to commonly used HRV analysis, with regard to i) the ability to detect changes in ANS activity and ii) inter-subject variability. This study was performed in seven sheep fetuses. In order to evaluate the sensitivity and specificity of our index in evaluating parasympathetic activity, we directly administered 2.5 mg intravenous atropine, to inhibit parasympathetic tone, and 5 mg propranolol to block sympathetic activity. Our index, as well as time analysis (root mean square of the successive differences; RMSSD) and spectral analysis (high frequency (HF) and low frequency (LF) spectral components obtained via fast Fourier transform), were measured before and after injection. Inter-subject variability was estimated by the coefficient of variance (%CV). In order to evaluate the ability of HRV parameters to detect fetal parasympathetic decrease, we also estimated the effect size for each HRV parameter before and after injections. As expected, our index, the HF spectral component, and the RMSSD were reduced after the atropine injection. Moreover, our index presented a higher effect size. The %CV was far lower for our index than for RMSSD, HF, and LF. Although LF decreased after propranolol administration, fetal stress index, RMSSD, and HF were not significantly different, confirming the fact that those indexes are specific to the parasympathetic nervous system. In conclusion, our method appeared to be effective in detecting parasympathetic inhibition. Moreover, inter-subject variability was much lower, and effect size higher, with our method compared to other HRV analysis methods.