Task-related Fatigue Research Articles

Human reliability assessment in hydrogen refuelling stations: A system dynamic approach

This study develops a methodology using a system dynamics approach to analyse human error probability (HEP) within the context of hydrogen fuelling station (HFS) maintenance, mainly focusing on the dynamic nature of performance shaping factors (PSFs) over time. The developed model offers a comprehensive understanding of how diverse human factors dynamically influence task performance, yielding critical insights for safety management strategies to study 8-hour day shifts in maintenance activity. The study explores the intricate relationship between time-dependent PSFs and human error probability, highlighting that as the number of maintenance tasks rises, so does the potential for increased fatigue levels, subsequently elevating HEP. Introducing breaks during work emerges as a promising intervention to mitigate task-related fatigue, reducing HEP. Careful break implementation is necessary to prevent shifts from extending, which could inadvertently raise HEP. This research has implications extending beyond HFS, benefiting industries where operational safety and efficiency are paramount. Future studies can build upon these findings, exploring additional interventions and diverse work scenarios to advance our understanding of human performance and error prevention strategies, ultimately fostering safer and more productive work environments. The integration of system dynamics and the insights gained contribute significantly to hydrogen safety and offer a robust foundation for future investigations in this field.

A - 174 The Clinical Utility of RBANS Coding Compared to WAIS-IV PSI in Community Dwelling Older Adults.

Fatigue and cognitive performance are important considerations in assessment with older adults. Utilization of a shorter cognitive battery may provide similar results to lengthier batteries in older adults diagnosed with various degenerative diseases (Mooney et al., 2007). Studies have identified implications for both normative and abnormal cognitive decline with regard to task-related fatigue (Campbell et al., 2022; Hess & Knight, 2021). When examining processing speed and mental fatigue, research has identified strong associations in clinical populations (Andreasen et al., 2010; Hess & Knight, 2021; Banerjee et al., 2020). The current study compares longer and shorter measures of cognitive processing speed in a community dwelling older adult sample. bThe current sample consists of 60 community dwelling participants (female n = 54; Caucasian n = 52); mean education 13.83years; mean age = 76years. Measures: Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Coding; Wechsler Adult Intelligence Scale Fourth Edition (WAIS-IV) Symbol Search (SS) and Coding (CD) subtests. Linear regression identified that 82.7% of the variance in RBANS Coding was accounted for by WAIS-IV SS and CD (Adjusted R Squared = 0.827). The specific correlations for RBANS Coding were strong for SS (r = 0.794, p < 0.001) and CD (r = 0.907, p < 0.001). RBANS Coding appears to map on strongly to the WAIS PSI in community dwelling older adult populations. RBANS Coding may be considered as an alternative to longer measures of processing speed due to the strong correlation to better established PSI measures on the WAIS.

Remote Cochlear Implant Assessments: Validity and Stability in Self-Administered Smartphone-Based Testing.

The stability of remote testing in cochlear implant care was studied by testing the influence of time-of-day, listener fatigue, and motivation on the outcomes of the aided threshold test (ATT) and digit triplets test (DTT) in cochlear implant (CI) recipients using self-tests at-home on a smartphone or tablet. A single-center repeated measures cohort study design (n = 50 adult CI recipients). The ATT and DTT were tested at-home ten times, with nine of these sessions planned within a period of eight days. Outcomes were modeled as a function of time-of-day, momentary motivation, listeners' task-related fatigue, and chronotype (i.e., someone's preference for morning or evening due to the sleep-wake cycle) using linear mixed models. Additional factors included aided monosyllabic word recognition in quiet, daily-life fatigue, age, and CI experience. Out of 500 planned measurements, 407 ATTs and 476 DTTs were completed. The ATT determined thresholds and impedances were stable across sessions. The factors in the DTT model explained 75% of the total variance. Forty-nine percent of the total variance was explained by individual differences in the participants' DTT performance. For each 10% increase in word recognition in quiet, the DTT speech reception threshold improved by an average of 1.6 dB. DTT speech reception threshold improved, on average by 0.1 dB per repeated session and correlated with the number of successful DTTs per participant. There was no significant time-of-day effect on auditory performance in at-home administered tests. This study is one of the first to report on the validity and stability of remote assessments in CI recipients and reveals relevant factors. CI recipients can be self-tested at any waking hour to monitor performance via smartphone or tablet. Motivation, task-related fatigue, and chronotype did not affect the outcomes of ATT or DTT in the studied cohort. Word recognition in quiet is a good predictor for deciding whether the DTT should be included in an individual's remote test battery. At-home testing is reliable for cochlear implant recipients and offers an opportunity to provide care in a virtual hearing clinic setting.

Sleep and task related fatigue in automated vehicles: Measures and countermeasures

Sleep and task related fatigue in automated vehicles: Measures and countermeasures

Adult Age Differences in the Effects of Chronic Mental Fatigue on Task-Related Fatigue, Appraisals, and Performance.

Engagement in potentially beneficial activities is assumed to be based partially on perceived costs and benefits. Mental fatigue may be one factor that affects perceived costs. We examined age differences in both chronic and situational mental fatigue, and their relation to task perceptions and engagement levels. Younger (M age = 32.6) and older (M age = 73.1) adults completed questionnaires measuring subjective mental fatigue, physical and mental health, and motivational states, along with several assessments of cognitive ability. In addition, assessments of effort expenditure (systolic blood pressure) and task difficulty were collected during performance of a cognitively demanding memory-scan task. Two components of chronic mental fatigue (CMF) relating to affect and motivation were identified. Although the structure of CMF did not vary with age, CMF was differentially predictive of engagement and appraisal levels across groups. As CMF-Affect levels increased, older adults' task-difficulty appraisals increased more than those of younger adults. In addition, CMF-Affect was positively associated with levels of engagement in the young, but negatively associated in the old as memory load increased. Older adults also exhibited higher levels of situational fatigue than did the young, as evidenced by increased levels of effort expenditure as both time on task and objective demands increased. However, little relationship existed between chronic and situational mental fatigue in either age group. These findings suggest that the affective aspect of CMF is particularly consequential in older adults, with both task appraisals and engagement levels being negatively affected when fatigue is high.

Exploration of the effects of task-related fatigue on eye-motion features and its value in improving driver fatigue-related technology

Mental fatigue has been lacked attention in developing eye-tracking fatigue detection system for drivers. However, it has great influence on eye movement which could account for the poor validity of current fatigue detectors only focusing on sleep-related fatigue. This work sought to investigate the influence of two types of task-related mental fatigue on eye movement by examining 8 saccade-based, 3 blink-based, and 1 pupil-based metrics. We propose that two types of task-related fatigue caused by cognitive overload and prolonged underload will induce different physiological responses to eye-motion features. Twenty participants completed a vigilance task before and after a 1-h driving with a secondary task in a virtual simulation environment, while forty participants, divided equally into two groups, finished the same task before and after a 1-h and 1.5-h monotonous driving. T-test was applied to analyse the eye-motion, subjective and vigilance data during vigilance task. We found that overload driving made drivers vigilance ability decrease. The eye metrics showed different changes in underload and overload scenario. The blink duration, the mean velocity of saccade and saccade duration increased after 1-h overload driving, while the pupil diameter decreased. However, none of those changes were observed in 1.5-h underload driving, but saccade duration had a significant increase. The fatigue response to heavy demands over short periods of driving is different from the lighter demands over long periods in terms of eye-motion metrics. Considering mental fatigue in designing an eye-tracking fatigue detection system could possibly improve its accuracy.

Potentialities of Vehicle Trajectory Big Data for Monitoring Potentially Fatigued Drivers and Explaining Vehicle Crashes on Motorway Sections

Task-related fatigue, caused by prolonged driving, is a major cause of vehicle crashes. Despite noticeable academic achievements, monitoring drivers’ fatigue on road sections is still an ongoing challenge which must be met to prevent and reduce traffic accidents. Fortunately, individual instances of vehicle trajectory big data collected through advanced vehicle-GPS systems offer a strong opportunity to trace driving durations. We propose a new approach by which to monitor task-related fatigued drivers by directly using the ratio of potentially fatigued drivers (RFD) to all drivers for each road section. The method used to compute the RFD index was developed based on two inputs: the distribution of the driving duration (extracted from vehicle trajectory data), and the boundary condition of the driving duration between fatigued and non-fatigued states. We demonstrate the potentialities of the method using vehicle trajectory big data and real-life traffic accident data. Results showed that the measured RFD has a strong explanatory power with regard to the traffic accident rate, with a statistical correlation of 0.86 at least, for regional motorway sections. Therefore, it is expected that the proposed approach is a feasible means of successfully monitoring fatigued drivers in the present and near future era of smart-mobility big data.

Causal Factors and Symptoms of Task-Related Human Fatigue in Vessel Traffic Service: A Task-Driven Approach

Human fatigue is a major risk factor in transportation that contributes, directly or indirectly, to a large number of traffic accidents. Though many studies have investigated fatigue-inducing factors in transportation to manage human fatigue more efficiently, there are limited studies related to vessel traffic service (VTS). To fill this gap, this work aims to determine the key causal factors and symptoms of human fatigue with a focus on VTS operations. Achieving this aim is hindered by the problems of no standard definition of task-related fatigue and limited data sources. To solve these problems, this paper proposes a novel definition of task-related human fatigue, a task-driven approach for identifying causal factors and a causal network-based approach for selecting key causal factors. Twelve key causal factors of human fatigue in VTS were identified and analysed. In addition, it was found that VTS operators suffered from multidimensional fatigue, especially physical fatigue. The results provide a foundation and future directions for designing interventions to manage human fatigue.

Effects of a Motion Seat System on Driver's Passive Task-Related Fatigue: An On-Road Driving Study.

Passive task-related (TR) fatigue caused by monotonous driving can negatively affect driving safety by impairing driver alertness and performance. This study aims to evaluate the effectiveness of a motion seat system on the driver’s passive TR fatigue in terms of driving performance, physiological response, and subjective fatigue by using automotive and physiological sensors those applicable to on-road driving environment. Twenty drivers (5 females and 15 males; age = 38.5 ± 12.2) with more than two years of driving experience participated in an on-road experiment with two driving conditions: driving in the static seat condition during the first half of the driving session and then in the static (static–static, SS) or motion seat (static–motion, SM) condition during the second half. The SM condition showed significantly lower passive TR fatigue by 4.4~56.5% compared to the SS condition in terms of the standard deviation of velocity, percentage of eyelid closure rate (PERCLOS), and the ratio of low- to high-frequency power (LF/HF) of electrocardiography signals. The drivers rated significantly lower subjective state changes of overall fatigue, mental fatigue, passive TR fatigue, drowsiness, and decreased concentration in the SM condition than those in the SS condition. The findings of the study support the use of a motion seat system can be an effective countermeasure to reduce passive TR fatigue.

Evaluation of a Motion Seat System for Reduction of a Driver’s Passive Task-Related (TR) Fatigue

A passive task-related (TR) fatigue that occurs monotonous driving environment can degrade driver's alertness and performance, thereby impairing driving safety. This study evaluated the driver's passive TR fatigue reduction effect of the motion seat system in terms of driving performance, physiological response, and subjective fatigue. 17 Korean drivers (6 females and 11 males) measured the driving performance (standard deviation of lane position, SDLP; break reaction time, BRT), percentage of eye closure (PERCLOS), and standard deviation of NN interval (SDNN) of the ECG during simulated driving for 90 minutes on a monotonous highway. The evaluation of the driving consisted of the first half (45 min) and the second half (45 min), while static seat condition in the first half and seat motion (bow, wave motion profile) condition in the second half. During static seat condition driving, SDLP, BRT, and PERCLOS were significantly higher (α = .05) in the second half compared with first half by 6.0 cm, 92.8 msec and 1.3%, respectively. However, there was no significant difference between first half and second half under motion seat conditions. In addition, subjective passive mental fatigue was observed to be 1.2 times lower during motion seat conditions than static seat condition ( p &lt; 0.01). The results of this study indicated that motion seat system have some effect on the driver’s passive TR fatigue reduction. Our findings may not extend to on road driving condition because we tested only simulation driving condition. Therefore, effect of motion seat system on driver’s passive TR fatigue need to be evaluated in future studies under real road condition.

Asleep at the automated wheel—Sleepiness and fatigue during highly automated driving

Due to the lack of active involvement in the driving situation and due to monotonous driving environments drivers with automation may be prone to become fatigued faster than manual drivers (e.g. Schömig et al., 2015). However, little is known about the progression of fatigue during automated driving and its effects on the ability to take back manual control after a take-over request. In this driving simulator study with Nö=ö60 drivers we used a three factorial 2ö×ö2ö×ö12 mixed design to analyze the progression (12ö×ö5ömin; within subjects) of driver fatigue in drivers with automation compared to manual drivers (between subjects). Driver fatigue was induced as either mainly sleep related or mainly task related fatigue (between subjects). Additionally, we investigated the drivers’ reactions to a take-over request in a critical driving scenario to gain insights into the ability of fatigued drivers to regain manual control and situation awareness after automated driving.Drivers in the automated driving condition exhibited facial indicators of fatigue after 15 to 35ömin of driving. Manual drivers only showed similar indicators of fatigue if they suffered from a lack of sleep and then only after a longer period of driving (approx. 40ömin). Several drivers in the automated condition closed their eyes for extended periods of time. In the driving with automation condition mean automation deactivation times after a take-over request were slower for a certain percentage (about 30%) of the drivers with a lack of sleep (Mö=ö3.2; SDö=ö2.1ös) compared to the reaction times after a long drive (Mö=ö2.4; SDö=ö0.9ös). Drivers with automation also took longer than manual drivers to first glance at the speed display after a take-over request and were more likely to stay behind a braking lead vehicle instead of overtaking it.Drivers are unable to stay alert during extended periods of automated driving without non-driving related tasks. Fatigued drivers could pose a serious hazard in complex take-over situations where situation awareness is required to prepare for threats. Driver fatigue monitoring or controllable distraction through non-driving tasks could be necessary to ensure alertness and availability during highly automated driving.

Driven to discussion: engaging drivers in conversation with a digital assistant as a countermeasure to passive task‐related fatigue

Using a Wizard-of-Oz approach, we explored the effectiveness of engaging drivers in conversation with a digital assistant as an operational strategy to combat the symptoms of passive task-related fatigue. Twenty participants undertook two 30-minute drives in a medium-fidelity driving simulator between 13:00 and 16:30, when circadian and homeostatic influences naturally reduce alertness. Participants were asked to follow a lead-car travelling at a constant speed of 68mph, in a sparsely-populated UK motorway scenario. During one of the counterbalanced drives, participants were engaged in conversation by a digital assistant (‘Vid’). Results show that interacting with Vid had a positive effect on driving performance and arousal, evidenced by better lane-keeping, earlier response to a potential hazard situation, larger pupil diameter, and an increased spread of attention to the road-scene (i.e. fewer fixations concentrated on the road-centre indicating a lower incidence of ‘cognitive tunnelling’). Drivers also reported higher levels of alertness and lower sleepiness following the Vid drive. Subjective workload ratings suggest that drivers exerted less effort to ‘stay awake’ when engaged with Vid. The findings support the development and application of in-vehicle natural language interfaces, and can be used to inform the design of novel countermeasures for driver fatigue.

The effects of exercise fatigue on prefrontal and motor activations as measured by near-infrared spectroscopy.

This study aimed to examine the effects of active task-related fatigue induced by maximal exercise on human cognitive and motor systems. To achieve the goal, we measured participants' activation changes in their prefrontal and motor cortices while performing an incremental cycling task using near-infrared spectroscopy (NIRS). The participant's task was to ride a test bike to maximal exertion twice within 2 days in a low-load and a high-load condition, respectively. The behavioral data showed longer cycling time in the low-load condition than that in the high-load condition. By contrast, the NIRS data showed greater prefrontal activations in the low-load condition than that in the high-load condition. More importantly, both the prefrontal and motor activations increased significantly near maximal exertion and then decreased in the initial recovery period, and the activation changes in the left prefrontal cortex resulted in changes in the bilateral motor areas. The results directly indicate the critical role of prefrontal cortex in fatigue and suggest that NIRS is an appropriate brain-imaging tool to monitor fatigue in natural environments.

Drivers' Attitude Towards Caffeine Chewing Gum As Countermeasure To Driver Task-Related Fatigue

Abstract: Driver fatigue is one of the major contributors to road accidents. In this study, we refer to task-related fatigue, in contrast to sleep-related fatigue. Sleep-related fatigue decrements in driving performance are related to the circadian rhythm, sleep disorders, and sleep deprivation or restriction. Task-related fatigue depends on driving conditions: active and passive task-related fatigue may arise according to the combination of driving task and driving environment. Active task-related fatigue is related to overload driving conditions, and passive task-related fatigue with underload ones. Several countermeasures have been proposed to face the problem of driver fatigue, such as taking a nap or caffeine beverages. The intake of caffeine has shown the enhancement of vigilance and choice reaction time. Those enhancements have an effect within 5-10 min in a caffeine chewing gum compared with 30 to 45 min in coffee. The enhancement in alertness within 5 min is crucial and potentially can reduce sleep related car accidents. Recent study showed that the caffeine effect is directly related to driving performance in monotonous conditions. In this study, two groups of drivers were asked to provide their preferences on several products that might positively affect their driving performance on long and monotonous conditions. The first group composed of participants that drove a driving simulator and actually consumed the products. The second group was composed of questionnaire responders that were presented with animations replicating the first group's actual driving. Both groups’ participants preferred to consume coffee or regular chewing-gum over caffeine chewing gum when asked at the beginning of the experiment (or survey). Drivers that actually consumed the products changed their attitude in favour of caffeine chewing-gum. On the other hand, the drivers that participated in the survey did not change their attitude, but rather changed their attitude with regards to the safety in using caffeine chewing-gum.

Static and dynamic functional connectivity in patients with chronic fatigue syndrome: use of arterial spin labelling fMRI.

Studies using arterial spin labelling (ASL) have shown that individuals with chronic fatigue syndrome (CFS) have decreased regional cerebral blood flow, which may be associated with changes in functional neural networks. Indeed, recent studies indicate disruptions in functional connectivity (FC) at rest in chronically fatigued patients including perturbations in static FC (sFC), that is average FC at rest between several brain regions subserving neurocognitive, motor and affect-related networks. Whereas sFC often provides information of functional network reorganization in chronic illnesses, investigations of temporal changes in functional connectivity between multiple brain areas may shed light on the dynamic characteristics of brain network activation associated with such maladies. We used ASL fMRI in 19 patients with CFS and 15 healthy controls (HC) to examine both static and dynamic changes in FC among several a priori selected brain regions during a fatiguing cognitive task. HC showed greater increases than CFS in static FC (sFC) between insula and temporo-occipital structures and between precuneus and thalamus/striatum. Furthermore, inferior frontal gyrus connectivity to cerebellum, occipital and temporal structures declined in HC but increased in CFS. Patients also showed lower dynamic FC (dFC) between hippocampus and right superior parietal lobule. Both sFC and dFC correlated with task-related fatigue increases. These data provide the first evidence that perturbations in static and dynamic FC may underlie chronically fatigued patients' report of task-induced fatigue. Further research will determine whether such changes in sFC and dFC are also characteristic for other fatigued individuals, including patients with chronic pain, cancer and multiple sclerosis.

Cerebellar cathodal tDCS interferes with recalibration and spatial realignment during prism adaptation procedure in healthy subjects

The aim of this study is to clarify the specific role of the cerebellum during prism adaptation procedure (PAP), considering its involvement in early prism exposure (i.e., in the recalibration process) and in post-exposure phase (i.e., in the after-effect, related to spatial realignment). For this purpose we interfered with cerebellar activity by means of cathodal transcranial direct current stimulation (tDCS), while young healthy individuals were asked to perform a pointing task on a touch screen before, during and after wearing base-left prism glasses. The distance from the target dot in each trial (in terms of pixels) on horizontal and vertical axes was recorded and served as an index of accuracy. Results on horizontal axis, that was shifted by prism glasses, revealed that participants who received cathodal stimulation showed increased rightward deviation from the actual position of the target while wearing prisms and a larger leftward deviation from the target after prisms removal. Results on vertical axis, in which no shift was induced, revealed a general trend in the two groups to improve accuracy through the different phases of the task, and a trend, more visible in cathodal stimulated participants, to worsen accuracy from the first to the last movements in each phase. Data on horizontal axis allow to confirm that the cerebellum is involved in all stages of PAP, contributing to early strategic recalibration process, as well as to spatial realignment. On vertical axis, the improving performance across the different stages of the task and the worsening accuracy within each task phase can be ascribed, respectively, to a learning process and to the task-related fatigue.

Driver state examination—Treading new paths

A large proportion of crashes in road driving can be attributed to driver fatigue. Several types of fatigue are discussed, comprising sleep-related fatigue, active task-related fatigue (as a consequence of workload in demanding driving situations) as well as passive task-related fatigue (as related to monotonous driving situations). The present study investigated actual states of fatigue in a monotonous driving situation, using EEG measures and a long-lasting driving simulation experiment, in which drivers had to keep the vehicle on track by compensating crosswind of different strength. Performance data and electrophysiological correlates of mental fatigue (EEG Alpha and Theta power, Inter Trial Coherence (ITC), and auditory event-related potentials to short sound stimuli) were analyzed. Driving errors and driving lane variability increased with time on task and with increasing crosswind. The posterior Alpha and Theta power also increased with time on task, but decreased with stronger crosswind. The P3a to sound stimuli decreased with time on task when the crosswind was weak, but remained stable when the crosswind was strong. The analysis of ITC revealed less frontal Alpha and Theta band synchronization with time on task, but no effect of crosswind. The results suggest that Alpha power in monotonous driving situations reflects boredom or attentional withdrawal due to monotony rather than the decline of processing abilities as a consequence of high mental effort. A more valid indicator of declining mental resources with increasing time on task seems to be provided by brain oscillatory synchronization measures and event-related activity.

Caffeinated Chewing Gum as Countermeasure to Drivers’ Passive Task-Related Fatigue Caused by Monotonous Roadway

This study analyzed driver passive task-related fatigue caused by a monotonous environment and the effectiveness of caffeinated chewing gum as a countermeasure. Data collected by a driving simulator in the laboratory were used to measure changes in driving performance. A self-perceived measure of fatigue was also analyzed. Seventy-two subjects were asked to drive for 70 min along a straight road after receiving one of the following substances (treatments): caffeinated chewing gum, a cup of coffee, or placebo chewing gum. The 72 subjects were subdivided into three groups of 24 each, and all participants were asked to take part in two driving sessions: one control drive without administration (no treatment) and one with administration (one of the treatments). The negative effects on driving performance of prolonged driving and the effectiveness of the standard deviation of the lateral position in representing worsening driving performance were demonstrated. This analysis indicated that intake of caffeine in the form of caffeinated chewing gum (100 mg caffeine) improved driving performance in less than 10 min. Drinking an ordinary cup of coffee (with the same caffeine content) did not improve driving performance in the same short time interval.

Effects of Driver Task-related Fatigue on Driving Performance

In this study, passive task-related fatigue effects on highway driving were analyzed by means of driving simulator experiments. Ten drivers were asked to drive in various environments in the morning (9:00-11:00 a.m.) and early afternoon (1:00-3:00 p.m.). Mean of Absolute Steering Error and Standard Deviation of Lateral Position, calculated on sub-intervals of 4minutes, were analysed as response variables. The results confirmed the negative influence of the duration of driving tasks and circadian effects on driving performance, increasing the likelihood of “near misses” and accidents.

Analysis of driver task-related fatigue using driving simulator experiments

In this paper passive task-related effects of highway driving in monotonous environments were studied using driving simulator experiments. Seventeen drivers were asked to drive in monotonous and various environments in the morning (9:00-11:00 a.m.) and in the early afternoon (1:00-3:00 p.m.); the Mean and the Standard Deviation of Steer Error and the Standard Deviation of Lateral Position, calculated on sub-interval of 1minute, were recorded and chosen as response variables. The analysis conducted using mixed-effects models highlighted negative influence of the duration of driving task, monotonous environment and circadian effects in decrements of driving performances.