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Reader fatigue – Electroencephalography findings: A case study in students
Abstract
Background:
Mental fatigue is usually accompanied by a sense of weariness, reduced alertness, and reduced mental performance, which can lead to accidents, decrease of productivity in workplace and several other health hazards.
Objective:
The aim of this study was to assess mental fatigue of students while reading for a prolonged duration of time by application of electroencephalography (EEG).
Methods:
Ten healthy students (27.57±3.4 years; 5 females and 5 males), participated in the study. The experimental design consisted of 5 blocks of 15-min length, in total 75 min for each participant. The experiment was done without any reading activities at the first block. In the following, participants studied the texts and corrected the mistakes. In each block EEG (beta, alpha, and theta power), and the Karolinska Sleepiness Scale (KSS) were recorded.
Results:
The mean of the self-assessment of sleepiness by KSS from the first to final 15 minutes were 2.3, 3.4, 4.3, 5.2, and 6.1, respectively. The average power in the theta band decreased from 1.23μV2/Hz at the first 15-min period to 1.02μV2/Hz at the last 15-min period. Also, mean power in the alpha band decreased from 0.85μV2/Hz at the first 15-min period to 0.59μV2/Hz at the last 15-min period.
Conclusion:
The study showed that the KSS and EEG activity indicate sleepiness which were highly correlated, with both changing along with performance.
... The presence of suitable lighting and its optimal distribution in such environments can reduce the incidence of eyestrain and reduction of accuracy. If individuals are exposed to unsuitable lighting, the real information might be lost, and the risk of mistakes by human resources and students increases (11,14). ...
Background: A lack of enough light in educational-academic spaces causes a wide range of damages and, most importantly, a destructive effect on the learning of students and researchers. Objectives: In this study, the intensity of light (in terms of lux) in the classrooms and laboratories of the faculties of health and paramedicine, medicine, nursing and midwifery, and dentistry of Qazvin University of Medical Sciences, Qazvin, Iran, was measured in 2020. Methods: In this descriptive-cross-sectional study, the numbers of classes and laboratories were 35 and 23, respectively. Natural and artificial light measurements were carried out in the morning and evening. The average readings were compared to international and national standards. Data analysis was performed using R software (version 4.1.0). Results: The classes of the Faculty of Dentistry and Faculty of Medicine had the highest and lowest average intensity of general and artificial lighting, respectively. Moreover, 78% and 82.4% of the general lighting intensity readings in the morning and evening were within the standard range, respectively. However, only 36.8% and 26% of the total readings of artificial light intensity in the morning and evening were outside the defined standard range, respectively. The classes with western and eastern windows had significantly higher general lighting intensity than the northern geographic windows (P < 0.001). Conclusions: In the classrooms and laboratories of Qazvin University of Medical Sciences, the general and artificial lighting in the Faculty of Medicine classrooms and in the majority of laboratories need to be improved.
Background:
In developing countries, construction is a largely manual job that imposes awkward postures on workers, thus facilitating a variety of musculoskeletal disorders. Ergonomic training is known as an effective way to reduce these disorders.
Objective:
This study aimed to evaluate the effectiveness of ergonomic training intervention in reducing the ergonomic risk of concrete form workers.
Methods:
This quasi-experimental study was carried out on 144 concrete form workers employed in the construction projects of Gonbad-e Kāvus, Iran, Iran. Data was collected using the Nordic Musculoskeletal Questionnaire (at the pre-intervention stage) and the Rapid Entire Body Assessment (REBA) worksheet (at the pre- and post-intervention stages). Ergonomic training was provided via face-to-face educational meetings along with presenting informative pamphlets, which took place over 45 days duration of time. Data were analyzed by the use of SPSS software version 21, t-test and Wilcoxon test. Significant level was considered at P-value less than 0.05.
Results:
Musculoskeletal disorders were observed in all limbs of the studied workers. The most prevalent disorders were the pain in the shoulder region of lift operators (86.1%) and the pain in the back area of mixer operators (77.8%). About 99.3% of all concrete form workers were exposed to a moderate level of ergonomic risk and needed posture correction. Pre- and post-training REBA scores showed a statistically significant difference (P < 0.05).
Conclusion:
Although the ergonomic training did reduce the ergonomic risk of workers, because of its short duration, it failed to reduce this risk to an acceptable level. It is recommended to hold both theoretical and practical training sessions over longer periods of time.
Background and Objective
Organizational climate and organizational commitment have a tangible effect on organizational performance. This study aims to investigate organizational climate in a university of medical sciences along with organizational commitment and job burnout in the university staff.
Methods
This cross-sectional study is carried out via descriptive-analytical method on 250 employees of Torbat Heydariyeh University of Medical Sciences, Iran in 2016. Data collection tools include standard questionnaires of organizational climate, organizational commitment, and Maslach burnout inventory. Data analysis was carried out with SPSS software version 21 and Man-Whitney statistical tests, Kruskal-Wallis analysis, ANOVA, Chi-2, and Spearman’s correlation tests.
Results
Average age of the participants was 34.52 ± 7.70 including 55.6% men and 44.4% women. In the present study, organizational climate of employees was medium and high, and also, mean score of the organizational commitment of subjects was 66.11 ± 16.35. The highest amount of employees job burnout was related to low level (66%). Organizational climate among the employees lead to higher organizational commitment (r=0.472, P<0.001), and greater organizational climate and commitment contributes significantly towards a decrease in job burnout (r=-0.227, P<0.001; r=-0.335, P<0.001).
Conclusion
If the managers of these deputies pay more attention to the importance of the services of the health staff and manpower employed in this organization, they can improve the organizational commitment of healthcare workers and prevent their burnout, in order to maximize the quality of service delivery.
Introduction
Increasing population, the need for services, and industrialization of societies have led to a growing demand for shift work. Shiftwork causes several disorders, and determining the weight of each disorders is important for their prevention and treatment. Therefore, the purpose of the present study was to use Analytic Network Process (ANP) to prioritize and weigh shift work disorders among the personnel of hospitals of Kerman University of Medical Sciences.
Methods
This cross-sectional, descriptive-analytical study was conducted in 2017 among 300 shift work personnel of 10 public hospitals affiliated with Kerman University of Medical Sciences. ANP was used to prioritize and weigh shift work disorders. To this end, the criteria, sub-criteria, and alternatives were initially identified. Then, shift work disorders were categorized into 7 general criteria, 20 sub-criteria, and 3 alternatives. After designing the ANP and determining the effect of each criterion on the sub-criteria, the ANP questionnaire was developed and administered among the shift work personnel, who filled it out based on ANP. Super Decisions was subsequently used to weigh and prioritize shift work disorders.
Results
The results indicated that shift work disorders among the nurses included sleep disorders (0.297), psychological disorders (0.275), digestive disorders (0.137), personal life disorders (0.122), etc., in that order of weighing. With respect to the support staff, the major shift work disorders involved sleep disorders (0.252), digestive disorders (0.198), personal life disorders (0.168), and psychological disorders (0.164). Considering security personnel, the top four shift work disorders were sleep disorders (0.201), digestive disorders (0.186), psychological disorders (0.174), and personal life disorders (0.145).
Conclusion
According to the findings, sleep disorders had the highest weight in the three studied groups. Moreover, the night shift had the most profound effect on shift work disorders among the personnel in the three groups. It was followed by the evening shift. Morning shift had the lowest influence on shift work disorders. Therefore, the schedules should be taken to prevent these complications in the shift workers. It is suggested that work shift complications be included in the periodic examination program and, in case of discovery of any rhythmic disorder in each shift workers, the person should not remain in the shiftwork group for some time.
Abstract
Background
In both developed and developing countries, noise is regarded as the most common occupational hazard in various industries. The present study aimed to examine the effect of sound pressure level (SPL) on serum cortisol concentration in three different times during the night shift.
Methods
This case–control study was conducted among 75 workers of an industrial and mining firm in 2017. The participants were assigned to one of the three groups (one control and two case groups), with an equal number of workers (25 participants) in each group. Following the ISO 9612 standard, dosimetry was adopted to evaluate equivalent SPL using a TES-1345 dosimeter. The influence of SPL on serum cortisol concentration was measured during the night shift. The serum cortisol concentration was measured using a radioimmunoassay (RIA) test in the laboratory. Repeated measure analysis of variance and linear mixed models were used with α = 0.05.
Results
The results indicated a downward trend in the serum cortisol concentration of the three groups during the night shift. Both SPL and exposure time significantly affected cortisol concentration (p < 0.0001, p < 0.0001). Conversely, age and body mass index had no significant influence on cortisol concentration (p = 0.360, p = 0.62).
Conclusion
Based on the obtained results, increasing SPL will lead to enhancement of serum cortisol concentration. Given that cortisol concentration varies while workers are exposed to different SPLs, this hormone can be used as a biomarker to study the effect of noise-induced stress.
Mental fatigue is considered to be a contributing factor responsible for numerous road accidents and various medical conditions and the efficiency and performance could be impaired during fatigue. Hence, determining how to evaluate mental fatigue is very important. In the present study, ten subjects performed a long-term visual search task with electroencephalogram recorded, and self-assessment and reaction time (RT) were combined to verify if mental fatigue had been induced and were also used as confirmatory tests for the proposed measures. The changes in relative energy in four wavebands (δ,θ,α, and β), four ratio formulas [(α+θ)/β,α/β,(α+θ)/(α+β), and θ/β], and Shannon's entropy (SE) were compared and analyzed between the beginning and end of the task. The results showed that a significant increase occurred in alpha activity in the frontal, central, posterior temporal, parietal, and occipital lobes, and a dip occurred in the beta activity in the pre-frontal, inferior frontal, posterior temporal, and occipital lobes. The ratio formulas clearly increased in all of these brain regions except the temporal region, where only α/β changed obviously after finishing the 60-min visual search task. SE significantly increased in the posterior temporal, parietal, and occipital lobes. These results demonstrate some potential indicators for mental fatigue detection and evaluation, which can be applied in the future development of countermeasures to fatigue.
Workers' fatigue is a significant problem in modern industry, largely because of high demand jobs, long duty periods, disruption of circadian rhythms, and accumulative sleep debt that are common in many industries. Fatigue is the end result of integration of multiple factors such as time awake, time of day, and workload. Then, the full understanding of circadian biologic clock, dynamics of transient and cumulative sleep loss, and recovery is required for effective management of workplace fatigue. It can be more investigated in a new field of sleep medicine called occupational sleep medicine. Occupational sleep medicine is concerned with maintaining best productivity and safety in the industrial settings. The fatigue risk management system (FRMS) is a comprehensive approach that is based on applying scientific evidence of sleep knowledge to manage workers fatigue. It is developing rapidly in the highly safety demand jobs; especially truck drivers, pilots, and power plant workers. The objective of this review is to explain about fatigue in the workplace with emphasis on its association work performance and errors/accidents. Also, we discussed about different methods of fatigue measurement and management.
This study identified several physiological indices that can accurately monitor mental workload while participants performed multiple tasks with the strategy of maintaining stable performance and maximizing accuracy. Thirty male participants completed three 10-min. simulated multitasks: MATB (Multi-Attribute Task Battery) with three workload levels. Twenty-five commonly used mental workload measures were collected, including heart rate, 12 HRV (heart rate variability), 10 EEG (electroencephalography) indices (α, β, θ, α/θ, θ/β from O1-O2 and F4-C4), and two subjective measures. Analyses of index sensitivity showed that two EEG indices, θ and α/θ (F4-C4), one time-domain HRV-SDNN (standard deviation of inter-beat intervals), and four frequency-domain HRV: VLF (very low frequency), LF (low frequency), %HF (percentage of high frequency), and LF/HF were sensitive to differentiate high workload. EEG α/θ (F4-C4) and LF/HF were most effective for monitoring high mental workload. LF/HF showed the highest correlations with other physiological indices. EEG α/θ (F4-C4) showed strong correlations with subjective measures across diff erent mental workload levels. Operation strategy would affect the sensitivity of EEG α (F4-C4) and HF.
Background: Transition from pre-clinical to clinical training has been identified as a crucial stage of medical education regarding student stress. When entering the clinical environs, students may become more prone to burnout. Aims: This study aimed to determine the prevalence, sources and predictors of high stress levels and burnout among medical students at King Faisal University, Saudi Arabia, during the clinical phase of medical education. Subjects and Methods: A cross-sectional survey of medical students in years four through six at Al-Ahsa Medical College during the academic year 2011-12 was performed. All 324 regular course attendants were invited to participate in the study and 233 participated (response rate of 71.9%). A self-reported questionnaire was used which covered three categories, including 18 sources of stress. Short Perceived Stress Scale and Emotional Exhaustion Subscale of Maslach Burnout Inventory were used to measure stress and burnout. Result: Sixth year students were more likely to cite relationship, hospital, and professional issues as stressors. Top stressors cited by final year students were concern about the future, defective clinical practice skills, fear of harming patients, and high parental expectations. Whereas first year students cited stressors such as transportation problems to hospital, fear of infection, and time limitations for training. The prevalence of emotional exhaustion and high levels of perceived stress was 76.8 and 71.7% respectively. Year of study was the only single independent risk factor for burnout and high levels of stress among students of clinical years. Conclusions: Clinical phase of medical education is a necessary area of intervention in order to provide an improved transition between pre-clinical and clinical periods. In addition, adoption of a new curriculum that integrates pre-clinical and clinical training of students from an early stage of education may reduce the stress.
Mental fatigue was associated with increased power in frontal theta (θ) and parietal alpha (α) EEG rhythms. A statistical classifier can use these effects to model EEG-fatigue relationships accurately. Participants (n = 22) solved math problems on a computer until either they felt exhausted or 3 h had elapsed. Pre-and post-task mood scales showed that fatigue increased and energy decreased. Mean response times rose from 6.7 s to 7.9 s but accuracy did not change significantly. Mean power spectral densities or PSDs of θ and α bands rose by 29% and 44%, respectively. A kernel partial least squares classifier trained to classify PSD coefficients (1-18 Hz) of single 13-s EEG segments from alert or fatigued task periods was 91% to 100% accurate. For EEG segments from other task periods, the classifier outputs tracked the time course of the development of mental fatigue. By this measure, most subjects became substantially fatigued after 60 min of task performance. However, the trajectories of individual classifier outputs showed that EEG signs of developing fatigue were present in all subjects after 15-30 minutes of task performance. The results show that EEG can track the development of mental fatigue over time with accurate updates on a time scale a short as 13 seconds. In addition, the results agree with the notion that growing mental fatigue produces a shift away from executive and attention networks to default mode and is accompanied by a shift in alpha frequency to the lower alpha band.
Long lasting involvement in a cognitive task leads to mental fatigue. Substantial efforts have been undertaken to understand this phenomenon. However, it has been demonstrated that some changes with time on task are not only related to mental fatigue. The present study intends to clarify these effects of time on task unrelated to mental fatigue on response selection processes at the behavioural and electrophysiological level (using event-related potentials, ERPs). Participants had to perform a Simon task for more than 3 hours and rated their experienced mental fatigue and motivation to continue with the task at several time points during the experiment. The results show that at the beginning of the experiment some unspecific modulations of training and adaptation are evident. With time on task participants' ability to resolve response conflict appears to become impaired. The results reveal that time on task effects cannot be completely explained by mental fatigue. Instead, it seems that an interplay of adaptation at the beginning and motivational effects in the course of a task modulate performance and neurophysiological parameters. In future studies it will be important to account for the relative contribution of adaptation and motivation parameters when time on task effects are investigated.
Fatigue is a common worrying complaint among people performing physical activities on the basis of training or rehabilitation. An enormous amount of research articles have been published on the topic of fatigue and its effect on physical and physiological functions. The goal of this review is to focus on the effect of fatigue on muscle activity, proprioception, and cognitive functions and to summarize the results to understand the influence of fatigue on these functions. Attaining this goal provides evidence and guidance when dealing with patients and/or healthy individuals in performing maximal or submaximal exercises.
Some theoretical control models posit that the fatigue which is developed during physical
activity is not always peripheral and it is the brain which causes this feeling of fatigue. This fatigue
develops due to a decrease of metabolic resources to and from the brain that modulates physical
performance. Therefore, this research was conducted to find out if there was finite level of
metabolic energy resources in the brain, by performing both mental and physical activities to
exhaustion. It was found that there was an overflow of information during the exercise-involved
experiment. The circular relationship between fatigue, cognitive performance and arousal state
insinuates that one should apply more effort to maintain performance levels which would require
more energy resources that eventually accelerates the development of fatigue. Thus, there appeared
to be a limited amount of energy resources in the brain as shown by the cognitive performance of
the participants.
One of the current interests of exercise physiologists is to understand the nature
and control of fatigue related to physical activity to optimise athletic performance.
Therefore, this research focuses on the mathematical modelling and analysis of
the energy system pathways and the system control mechanisms to investigate
the various human metabolic processes involved both at rest and during exercise.
The first case study showed that the PCr utilisation was the highest energy
contributor during sprint running, and the rate of ATP production for each
anaerobic subsystem was similar for each athlete. The second study showed that
the energy expenditure derived from the aerobic and anaerobic processes for
different types of pacing were significantly different. The third study demonstrated
the presence of the control mechanisms, and their characteristics as well as
complexity differed significantly for any physiological organ system. The fourth
study showed that the control mechanisms manifest themselves in specific ranges
of frequency bands, and these influence athletic performance. The final study
demonstrated a significant difference in both reaction time and accuracy of the
responses to visual cues between the control and exercise-involved cognitive
trials. Moreover, the difference in the EEG power ratio at specific regions of the
brain; the difference in the ERP components’ amplitudes and latencies; and the
difference in entropy of the EEG signals represented the physiological factors in
explaining the poor cognitive performance of the participants following an
exhaustive exercise bout. Therefore, by using mathematical modelling and
analysis of the energy system pathways and the system control mechanisms
responsible for homeostasis, this research has expanded the knowledge how
performance is regulated during physical activity and together with the support of
the existing biological control theories to explain the development of fatigue during
physical activity.
Longer lasting performance in cognitively demanding tasks leads to an exhaustion of cognitive resources and to a state commonly described as mental fatigue. More specifically, the allocation and focusing of attention become less efficient with time on task. Additionally, the selection of even simple responses becomes more error prone. With respect to the recorded EEG, mental fatigue has been reported to be associated with an increase in frontal theta and frontal and occipital alpha activity. The present study focused on the time course of changes in behavior and in the EEG to characterize fatigue-related processes. Participants performed a spatial stimulus-response-compatibility task in eight blocks for an overall duration of four hours. Error rates increased continuously with time on task. Total alpha power was larger at the end compared to the beginning of the experiment. However, alpha power increased rapidly and reached its maximal amplitude already after one hour, whereas frontal theta showed a continuous increase with time on task, possibly related to increased effort to keep the performance level high. Time frequency analyses revealed power changes in the theta band induced by task relevant information that might be assigned to a drain of executive control capacities. Thus, frontal theta turned out to be a reliable marker of distinct changes in cognitive processing with increasing fatigue.
The study examined the relationships among justice, burnout, and academic achievement using a sample (N=1,505) of undergraduate university students. The study was conducted at a university in northern part of Cyprus. Hierarchical regression analysis was conducted to test the hypotheses. The results revealed that
distributive justice, procedural justice, and interactional justice were associated with burnout. In addition, distributive and interactional justice had a significant positive relationship with academic achievement. Procedural justice had no significant relationship with academic achievement while burnout had a negative association with students’ academic achievement. Additionally, burnout was treated as a mediator
between justice dimensions and academic achievement. The results of the Sobel test illustrated that burnout partially mediated the effect of distributive and interactional justice on academic achievement. The study provides discussion, limitations and directions for future research.
Electroencephalography (EEG) is widely used in cognitive and behavioral research. This study evaluates the effectiveness of using the EEG power index to measure visual fatigue. Three common visual fatigue measures, critical-flicker fusion (CFF), near-point accommodation (NPA), and subjective eye-fatigue rating, were used for comparison. The study participants were 20 men with a mean age of 20.4 yr. (SD = 1.5). The experimental task was a car-racing video game. Results indicated that the EEG power indices were valid as a visual fatigue measure and the sensitivity of the objective measures (CFF and EEG power index) was higher than the subjective measure. The EEG β and EEG α were effective for measuring visual fatigue in short- and long-duration tasks, respectively. EEG β/α were the most effective power indexes for the visual fatigue measure.
Objective:
Simple methods of sleepiness assessment are greatly needed for both fundamental research and practical applications. The Karolinska drowsiness test (KDT) was applied to construct physiological alertness scales and to validate them against such well-known instrument of subjective sleepiness assessment as the Karolinska sleepiness scale (KSS).
Methods:
Seven-min EEG recordings were obtained with 2-h interval from frontal and occipital derivations during the last 32-50 h of 44-61-h wakefulness of 15 healthy study participants. Occipital alpha-theta power difference and frontal and occipital scores on the 2nd principal component of the EEG spectrum were calculated for each one-min interval of 5-min eyes closed section of the record.
Results:
To obtain scores (from 0 to 5) on alertness scales for each of these EEG indexes, all positive one-min values of the index were assigned to 1, and all remaining (negative) values were assigned to 0. Scores on any of the physiological alertness scales were found to be strongly associated with KSS scores.
Conclusion:
Physiological analogues of KSS were offered by utilising the EEG recordings on eyes closed interval of KDT.
Significance:
The constructed physiological scales can help in improving validity and user-friendliness of the field and laboratory methods of quantification of drowsy state.
A framework for mental fatigue is proposed, that involves an integrated evaluation of both expected rewards and energetical costs associated with continued performance. Adequate evaluation of predicted rewards and potential risks of actions is essential for successful adaptive behaviour. However, while both rewards and punishments can motivate to engage in activities, both types of motivated behaviour are associated with energetical costs. We will review findings that suggest that the nucleus accumbens, orbitofrontal cortex, amygdala, insula and anterior cingulate cortex are involved evaluating both the potential rewards associated with performing a task, as well as assessing the energetical demands involved in task performance. Behaviour will only proceed if this evaluation turns out favourably towards spending (additional) energy. We propose that this evaluation of predicted rewards and energetical costs is central to the phenomenon of mental fatigue: people will no longer be motivated to engage in task performance when energetical costs are perceived to outweigh predicted rewards.
In this study we were interested to analyse the brain activity occurring during the “naturalistic” observation of commercial ads intermingled in a random order within a documentary. In order to measure both the brain activity and the emotional engage of the 15 healthy subjects investigated, we used simultaneous EEG, Galvanic Skin Response (GSR), Heart Rate (HR) recordings during the whole experiment. We would like to link significant variation of EEG, GSR, HR and Heart Rate Variability (HRV) measurements with the memory and pleasantness of the stimuli presented, as resulted successively from the subject’s verbal interview. In order to do that, different indexes were employed to summarize the cerebral and autonomic measurements performed. Such indexes were used in the statistical analysis, performed with the use of Analysis of Variance (ANOVA) and z-score transformation of the estimated cortical activity by solving the associated EEG inverse problem. The results are summarized as follows: (1) in the population analyzed, the cortical activity in the theta band elicited during the observation of the TV commercials that were remembered is higher and localized in the left frontal brain areas when compared to the activity elicited during the vision of the TV commercials that were forgotten (p
A skilled player in goal-directed sports performance has the ability to process internal and external information in an effective manner and decide which pieces of information are important and which are irrelevant. Focused attention and somatosensory information processing play a crucial role in this process. Electroencephalographic (EEG) recordings are able to demonstrate cortical changes in conjunction with this concept and were examined during a golf putting performance in an expert-novice paradigm. The success in putting (score) and performance-related cortical activity were recorded with an EEG during a 5 x 4 min putting series. Subjects were asked to putt balls for four min at their own pace. The EEG data was divided into different frequencies: Theta (4.75-6.75 Hz), Alpha-1 (7-9.5 Hz), Alpha-2 (9.75-12.5 Hz) and Beta-1 (12.75-18.5 Hz) and performance related power values were calculated. Statistical analysis shows significant better performance in the expert golfers (P < 0.001). This was associated with higher fronto-midline Theta power (P < 0.05) and higher parietal Alpha-2 power values (P < 0.05) compared to the novices in golf putting. Frontal Theta and parietal Alpha-2 spectral power in the ongoing EEG demonstrate differences due to skill level. Furthermore the findings suggest that with increasing skill level, golfers have developed task solving strategies including focussed attention and an economy in parietal sensory information processing which lead to more successful performance. In a theoretical framework both cortical parameters may play a role in the concept of the working memory.
Background:
According to the 2015 National Academy of Medicine report, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) "is a serious, chronic, complex, and systemic disease that frequently and dramatically limits the activities of affected patients." ME/CFS affects between 1 and 2.5 million Americans, leaving as many as 75% unable to work due to physical, cognitive and functional impairment. Unfortunately, many doctors and lawyers lack the knowledge of how to properly document an ME/CFS disability claim, leaving patients unable to access disability benefits.
Objective:
The goal of this article is to summarize the approaches used by experienced clinicians and lawyers in successful ME/CFS disability claims.
Methods:
The authors reviewed the types of US disability insurance programs and the evidence commonly required by these programs to demonstrate ME/CFS disability.
Results:
This article summarizes the range of methods used in successful US disability claims, which include documentation of the functional impact of post-exertional malaise and the use of methods that provide objective evidence of impairment.
Conclusions:
Medical providers and lawyers can use these tested methods to obtaining disability benefits for people with ME/CFS. Physical therapists, occupational therapists, and other specialists play an important role in providing objective evidence for ME/CFS disability claims.
Mental fatigue, a state of reduced alertness and decreased overall performance due to prolonged cognitive activity, is a major cause for a large number of accidents in traffic and industry. Against the background of an aging workforce, the investigation of the interconnection of mental fatigue and aging is of great practical relevance. In the present study, a group of younger and a group of older adults performed a cognitive task for 3 h. The experimental design also comprised breaks with various durations. Beside behavioral data, the spectral properties of the ongoing EEG with respect to time on task and breaks were analyzed. No differences between the age groups were found in behavior, but electrophysiological measures provide some evidence that older adults in our study were differentially affected by time on task. In the later course of the experiment modulations in frontal theta power became larger for older, compared to younger adults. This may indicate strain due to task demands, eventually resulting from the deployment of compensatory processes. Occipital alpha, which has been linked to internally oriented brain states, saturates faster in younger adults. It thus maybe, that especially the younger participants' performance deteriorated due to the monotonous nature of the task itself. Both mechanisms, an increased consumption of cognitive resources in older adults and a decrease of motivation in younger adults, could mask differences in performance decrements between the age groups due to mental fatigue.
Mental fatigue is a gradual and cumulative phenomenon induced by the time spent on a tedious but mentally demanding task, which is associated with a decrease in vigilance. It may be dangerous for operators controlling air traffic or monitoring plants. An index that estimates this state on-line from EEG signals recorded in 6 brain regions is proposed. It makes use of the Frobenius distance between the EEG spatial covariance matrices of each of the 6 regions calculated on 20s epochs to a mean covariance matrix learned during an initial reference state. The index is automatically tuned from the learning set for each subject. Its performance is analyzed on data from a group of 15 subjects who performed for 90 minutes an experiment that modulates mental workload. It is shown that the index based on the alpha band is well correlated with an ocular index that measures external signs of mental fatigue and can accurately assess mental fatigue over long periods of time.
Mental fatigue is an extremely sophisticated phenomenon, which is influenced by the environment, the state of health, vitality
and the capability of recovery. A single parameter cannot fully describe it. In this paper, the effects of long time sustained
low-workload visual display terminal (VDT) task on psychology are investigated by subjective self-reporting measures. Then
power spectral indices of HRV, the P300 components based on visual oddball and wavelet packet parameters of EEG are combined
to analyze the impacts of prolonged visual display terminal (VDT) activity on autonomic nervous system and central nervous
system. Finally, wavelet packet parameters of EEG are extracted as the features of brain activity in different mental fatigue
states. Kernel principal component analysis (KPCA) and support vector machine (SVM) are jointly applied to differentiate two
states. The statistic results show that the level of both subjective sleepiness and fatigue increase significantly from pre-task
to post-task, which indicate that the long time VDT task induces the mental fatigue to the subjects. The predominant activity
of autonomic nervous system of subjects turns to the sympathetic activity from parasympathetic activity after the task. The
P300 components and wavelet packet parameters of EEG are strongly related with mental fatigue. Moreover, the joint KPCA-SVM
method is able to effectively reduce the dimensionality of the feature vectors, speed up the convergence in the training of
SVM and achieve a high recognition accuracy (87%) of mental fatigue state. Multipsychophysiological measures and KPCA-SVM
method could be a promising tool for the evaluation of mental fatigue.
Drivers’ drowsiness is one of the main causes of car accidents or near-missed accidents. This has been proven by many studies that established links between driver's drowsiness and road accidents. The objective of this study was to analyze the EEG changes in fatigued subjects while performing a simulated driving task. After a night of sleep deprivation, eight subjects were given a dose of caffeine to reduce drowsiness. During about 50 min of continuous driving, car movements and subject behaviors were recorded on video cameras, and 8 channels of EEG were also recorded. Three basic indices, three ratio indices, and two burst indices were calculated from preprocessed EEG signals. EEG α,β, β/α and (α+θ)/β indices showed significant differences between driving periods. In the comparison of road type, EEG α,β, β/α and (α+θ)/β indices of the straight section of the driving task were significantly different from those of the curved section. This study also analyzed EEG changes before and after car accidents, showing that β and (α+θ)/β were related to the mental alertness level. In the analysis of burst activity, θ burst activity, which was not significant in the mean power analysis, was significantly different between driving sessions.Relevance to IndustryDriver's drowsiness is a major cause of serious traffic accidents. This study deals with time variant EEG change of sleep-deprived drivers—an important aspect of driver drowsiness analysis.The result of this study can be used to estimate overall alertness level of drivers.
This study investigated the changes in electroencephalography (EEG) activity in train drivers during a monotonous train-driving session. Four combinations of EEG activities were also compared to investigate the difference in performance of these equations. The four equations tested were equation 1 (θ/β), equation 2 (θ/(α + β)), equation 3 ((θ + α)/β), and equation 4 ((θ + α)/(α + β)). A total of fifty male train drivers were recruited to perform a 30-min monotonous train-driving task while 2-channels of EEG (frontal and temporal) were recorded. At the frontal site, significant differences were found for theta (p = 0.045) and alpha (0.0001) activities, and at the temporal site, significant differences were found for delta (p = 0.007) and theta (0.01) activities. For the average of frontal and temporal site activities, significant differences were found for delta (p = 0.004), theta (p = 0.001), and beta (p = 0.048). Significant difference were found for temporal site for equation 1 (θ/β) (p = 0.04), and equation 4 ((θ + α)/(α + β)) (p = 0.02), and for the average of frontal and temporal site activities, significant differences were found for all four equations (equation 1 (p = 0.001), equation 2 (p = 0.006), equation 3 (p = 0.04), and equation 4 (p = 0.002)). These findings can be utilised as a potential fatigue indicator.
Assessing brain wave activity is a viable strategy for monitoring fatigue when performing tasks such as driving, and numerous studies have been conducted in this area. However, results of a systematic review on changes in brain wave activity associated with fatigue have revealed equivocal findings. This study investigated brain wave activity associated with fatigue in 48 nonprofessional healthy drivers as they participated in a simulated driving task until they fatigued. The results showed that as a person fatigues, slow wave activity increased over the entire cortex, in theta and in alpha 1 and 2 bands, while no significant changes were found in delta wave activity. Substantial increases also occurred in fast wave activity, though mostly in frontal sites. The results suggest that as a person fatigues, the brain loses capacity and slows its activity, and that attempts to maintain vigilance levels lead to increased beta activity.
Mental fatigue is a contributing factor to some serious transportation crashes. In this study, we measured mental fatigue in drivers using electroencephalogram (EEG) and electrocardiograph (ECG). Together, thirteen healthy subjects performed a continuous simulated driving task for 90 min with simultaneous ECG and multi-channel EEG recording of each subject. Several important physiological parameters were investigated using preprocessed ECG and EEG signals. The results show that the EEG alpha and beta, the relative power, the amplitude of P300 wave of event-related potential (ERP), the approximated entropy of the ECG, and the lower and upper bands of power of heart rate variability (HRV) are significantly different before and after finishing the driving task (p<0.05). These metrics are possible indices for measuring simulated driving mental fatigue.
Focusing of attention is influenced by external features such as the presence of global or local target stimuli, but also by motivation and mood states. In the current study, we examined whether working on cognitively demanding tasks for 2 h, which induces mental fatigue, subsequently had a differential effect on global and local processing. The results showed that, compared to non-fatigued participants, fatigued participants particularly displayed compromised local processing. This indicates that mental fatigue may also manifest itself as effects on attentional focusing. The findings of this study are in line with recent ideas about the nature of fatigue-related cognitive deficits, implying disturbances in the control over attention and behaviour.
The Karolinska sleepiness scale (KSS) is frequently used for evaluating subjective sleepiness. The main aim of the present study was to investigate the validity and reliability of the KSS with electroencephalographic, behavioral and other subjective indicators of sleepiness.
Participants were 16 healthy females aged 33-43 (38.1+/-2.68) years. The experiment involved 8 measurement sessions per day for 3 consecutive days. Each session contained the psychomotor vigilance task (PVT), the Karolinska drowsiness test (KDT-EEG alpha & theta power), the alpha attenuation test (AAT-alpha power ratio open/closed eyes) and the KSS.
Median reaction time, number of lapses, alpha and theta power density and the alpha attenuation coefficients (AAC) showed highly significant increase with increasing KSS. The same variables were also significantly correlated with KSS, with a mean value for lapses (r=0.56).
The KSS was closely related to EEG and behavioral variables, indicating a high validity in measuring sleepiness.
KSS ratings may be a useful proxy for EEG or behavioral indicators of sleepiness.
Two feature selection approaches for multilevel mental fatigue electroencephalogram (EEG) classification are presented in this paper, in which random forest (RF) is combined with the heuristic initial feature ranking scheme (INIT) or with the recursive feature elimination scheme (RFE). In a "leave-one-proband-out" evaluation strategy, both feature selection approaches are evaluated on the recorded mental fatigue EEG time series data from 12 subjects (each for a 25-h duration) after initial feature extractions. The latter of the two approaches performs better both in classification performance and more importantly in feature reduction. RF with RFE achieved its lowest test error rate of 12.3% using 24 top-ranked features, whereas RF with INIT reached its lowest test error rate of 15.1% using 64 top-ranked features, compared to a test error rate of 22.1% using all 304 features. The results also show that 17 key features (out of 24 top-ranked features) are consistent between the subjects using RF with RFE, which is superior to the set of 64 features as determined by RF with INIT.
Participants first performed a scanning task that was weak (fatigue low) or strong (fatigue high) in self-regulatory (inhibitory) demand. They then were presented a cognitive challenge that had a strong regulatory component (the Stroop color-word conflict task) or a weak regulatory component (single-digit mental multiplication) with instructions that they would avoid noise if they attained a moderate performance standard. Analysis of cardiovascular data collected during the two work periods revealed fatigue main effects for systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure. The effects reflected stronger blood pressure responses for High Fatigue participants across work periods and regardless of the character of the challenge presented in work period 2. Results conceptually replicate previous mental fatigue findings, which have shown extension of fatigue influence across cognitive performance domains. At least as importantly, they also extend those findings by showing extension across a fresh and theoretically significant cognitive performance dimension.
Survey effect of illuminance source on alertness in a laboratory design
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Investigation of substance use prevalence and the interrelated factors involved through third-year high school students in Nazarabad city from
- N Ghavidel
- M Samadi
- A Kharmanbiz
- A Asadi
- A Feyzi
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Asleep at the Wheel: the Prevalence and Impact of Drowsy Driving. AAA foundation for traffic safety
- B C Tefft