Workload Ratings Research Articles

A system to determine advisory speed limits for horizontal curves based on mental workload and available sight distance

This study proposes a framework that accounts for mental workload and available sight distances to estimate advisory speed limits on horizontal curves. To achieve this goal, automated scripts were used to extract data on horizontal curve elements (i.e., the degree of curvature and the deflection angle), to detect crest vertical curves, and to compute the available sight distance from remote sensing data collected on highways in Alberta, Canada. Mental workload ratings were then assigned to each horizontal curve to calculate the perception–reaction time needed by drivers to maintain control of their vehicles while negotiating these curves. Finally, a curve advisory speed was calculated based on the available sight distance and the mental workload perception–reaction time needed to ensure a safe driving environment. This study presents a unique approach that incorporates human factors, including the responses of drivers based on their perception of the driving environment, in the development of speed advisory systems.

617 Does Wearing Enhanced Personal Protective Equipment (PPE) In Theatre Increase Surgeon Workload and Patient Morbidity?

IntroductionDelivery of surgical services during the Covid-19 pandemic has required the use of enhanced PPE in the operating theatre. We sought to evaluate the impact of this change on surgeon workload and intraoperative patient outcomes.MethodSurgeons performing as primary operator completed an online procedure-specific questionnaire on workload ratings for each operative case, using an extension of the validated Surgeon Task Load Index (SURG-TLX) tool (reported on a 20-point scale), together with operative details. Local approval was obtained at individual sites. Data was analysed in Stata SE v16.Results118 responses (17 surgeons, 7 specialties) were collected from June to September 2020. 77.1% used enhanced PPE. There was no association between enhanced PPE use and overall workload (p = 0.151) as measured with SURG-TLX, although surgeons wearing enhanced PPE commonly reported finding individual procedures harder than expected (37% vs 0%, p < 0.001). Communication was rated worse when using enhanced PPE use (MD -4.38, 95%CI -6.74 to 02.03; p < 0.001). There was no association between enhanced PPE use and intraoperative complications (p = 0.745).ConclusionsThe use of enhanced PPE is not associated with complications or increased surgeon workload assessed by SURG-TLX. It is, however, associated with difficulty in communicating, and subjectively experiencing more procedural challenge than anticipated.

Performance, Hemodynamics, and Stress in a Two-Day Vigilance Task: Practical and Theoretical Implications.

To explore vigilance task performance, cerebral blood flow velocity (CBFV), workload, and stress in a within-subjects, two-session experiment. Vigilance, or sustained attention, tasks are often characterized by a decline in operator performance and CBFV with time on task, and high workload and stress. Though performance is known to improve with practice, past research has not included measures of CBFV, stress, and workload in a within-subjects multi-session design, which may also provide insight into ongoing theoretical debate. Participants performed a vigilance task on two separate occasions. Performance, CBFV, workload, and self-reported stress were measured. Within each session, results were consistent with the vigilance profile found in prior research. Across sessions, performance improved but the time on task decrement remained. Mean CBFV and workload ratings did not differ between sessions, but participants reported significantly less distress, worry, and engagement after session two compared to one. Though practice may not disrupt the standard vigilance profile, it may serve to improve overall performance and reduce stress. However, repeated exposure may have negative implications for engagement and mind-wandering. It is important to better understand the relationship between experience, performance, physiological response, and self-reported stress and workload in vigilance because real-world environments often require operators to do the same task over many occasions. While performance improvement and reduced distress is an encouraging result, the decline in engagement requires further research. Results across sessions fail to provide support to the mind-wandering theory of vigilance.

Exploring the effectiveness of a digital voice assistant to maintain driver alertness in partially automated vehicles

Objective Vehicle automation shifts the driver's role from active operator to passive observer at the potential cost of degrading their alertness. This study investigated the role of an in-vehicle voice-based assistant (VA; conversing about traffic/road environment) to counter the disengaging and fatiguing effects of automation. Method Twenty-four participants undertook two drives– with and without VA in a partially automated vehicle. Participants were subsequently categorized into high and low participation groups (based on their proportion of vocal exchanges with VA). The effectiveness of VA was assessed based on driver alertness measured using Karolinska Sleepiness Scale (KSS), eye-based sleepiness indicators and glance behavior, NASA-TLX workload rating and time to gain motor readiness in response to take-over request and performance rating made by the drivers. Results Paired samples t-tests comparison of alertness measures across the two drives were conducted. Lower KSS rating, larger pupil diameter, higher glances (rear-mirror, roadside vehicles and signals in the drive with VA) and higher feedback ratings of VA indicated the efficiency of VA in improving driver alertness during automation. However, there was no significant difference in alertness or glance behavior between the driver groups (high and low-PR), although the time to resume steering control was significantly lower in the higher engagement group. Conclusion The study successfully demonstrated the advantages of using a voice assistant (VA) to counter these effects of passive fatigue, for example, by reducing the time to gain motor-readiness following a TOR. The findings show that despite the low engagement in spoken conversation, active listening also positively influenced driver alertness and awareness during the drive in an automated vehicle.

Cognitive plasticity induced by gaze-control technology: Gaze-typing improves performance in the antisaccade task

The last twenty years have seen the development of gaze-controlled computer interfaces for augmentative communication and other assistive technology applications. In many applications, the user needs to look at symbols on a virtual on-screen keyboard and maintain gaze to make a selection. Executive control is essential to learning to use gaze-control, affecting the uptake of the technology. Specifically, the user of a gaze-controlled interface must suppress looking for its own sake, the so-called “Midas touch” problem. In a pre-registered study (https://osf.io/2mak4), we tested whether gaze-typing performance depends on executive control and whether learning-dependent plasticity leads to improved executive control as measured using the antisaccade task. Forty-two university students were recruited as participants. After five 30-min training sessions, we found shorter antisaccade latencies in a gaze-control compared to a mouse-control group, and similar error-rates. Subjective workload ratings were also similar across groups, indicating the task in both groups was matched for difficulty. These findings suggest that executive control contributes to gaze-typing performance and leads to learning-induced plasticity.

Measuring Cognitive Load Using In-Game Metrics of a Serious Simulation Game.

Serious games have become an important tool to train individuals in a range of different skills. Importantly, serious games or gamified scenarios allow for simulating realistic time-critical situations to train and also assess individual performance. In this context, determining the user’s cognitive load during (game-based) training seems crucial for predicting performance and potential adaptation of the training environment to improve training effectiveness. Therefore, it is important to identify in-game metrics sensitive to users’ cognitive load. According to Barrouillets’ time-based resource-sharing model, particularly relevant for measuring cognitive load in time-critical situations, cognitive load does not depend solely on the complexity of actions but also on temporal aspects of a given task. In this study, we applied this idea to the context of a serious game by proposing in-game metrics for workload prediction that reflect a relation between the time during which participants’ attention is captured and the total time available for the task at hand. We used an emergency simulation serious game requiring management of time-critical situations. Forty-seven participants completed the emergency simulation and rated their workload using the NASA-TLX questionnaire. Results indicated that the proposed in-game metrics yielded significant associations both with subjective workload measures as well as with gaming performance. Moreover, we observed that a prediction model based solely on data from the first minutes of the gameplay predicted overall gaming performance with a classification accuracy significantly above chance level and not significantly different from a model based on subjective workload ratings. These results imply that in-game metrics may qualify for a real-time adaptation of a game-based learning environment.

Transfer of training—Virtual reality training with augmented multisensory cues improves user experience during training and task performance in the real world

Virtual reality (VR) can create safe, cost-effective, and engaging learning environments. It is commonly assumed that improvements in simulation fidelity lead to better learning outcomes. Some aspects of real environments, for example vestibular or haptic cues, are difficult to recreate in VR, but VR offers a wealth of opportunities to provide additional sensory cues in arbitrary modalities that provide task relevant information. The aim of this study was to investigate whether these cues improve user experience and learning outcomes, and, specifically, whether learning using augmented sensory cues translates into performance improvements in real environments. Participants were randomly allocated into three matched groups: Group 1 (control) was asked to perform a real tyre change only. The remaining two groups were trained in VR before performance was evaluated on the same, real tyre change task. Group 2 was trained using a conventional VR system, while Group 3 was trained in VR with augmented, task relevant, multisensory cues. Objective performance, time to completion and error number, subjective ratings of presence, perceived workload, and discomfort were recorded. The results show that both VR training paradigms improved performance for the real task. Providing additional, task-relevant cues during VR training resulted in higher objective performance during the real task. We propose a novel method to quantify the relative performance gains between training paradigms that estimates the relative gain in terms of training time. Systematic differences in subjective ratings that show comparable workload ratings, higher presence ratings and lower discomfort ratings, mirroring objective performance measures, were also observed. These findings further support the use of augmented multisensory cues in VR environments as an efficient method to enhance performance, user experience and, critically, the transfer of training from virtual to real environment scenarios.

Smart agent system for insulin infusion protocol management: a simulation-based human factors evaluation study

ObjectiveTo compare the insulin infusion management of critically ill patients by nurses using either a common standard (ie, human completion of insulin infusion protocol steps) or smart agent (SA) system...

Exploring the Peak-End Effects in Air Traffic Controllers' Mental Workload Ratings.

This study examined whether professional air traffic controllers (ATCos) were subject to peak-end effects in reporting their mental workload after performing an air traffic control task, and in predicting their mental workload in future scenarios. In affective experience studies, people's evaluation of a period of experience is strongly influenced by the most intense (peak) point and the endpoint. However, whether the effects exist in mental workload evaluations made by professional operators is still not known. In Study 1, 20 ATCos performed air traffic control scenarios on high-fidelity radar simulators and reported their mental workload. We used a 2 (high peak, low peak) × 2 (high end, low end) within-subject design. In Study 2, another group of 43 ATCos completed a survey asking them to predict their mental workload given the same air traffic control scenarios. In Study 1, ATCos reported higher mental workload after completing the high-peak and the high-end scenarios. In contrast, in Study 2, ATCos predicted the peak workload effect but not the end workload effect when asked to predict their experience in dealing with the same scenarios. Peak and end effects exist in subjective mental workload evaluation, but experts only had meta-cognitive awareness of the peak effect, and not the end effect. Researchers and practitioners that use subjective workload estimates for work design decisions need to be aware of the potential impact of peak and end task demand effects on subjective mental workload ratings provided by expert operators.

Driving Force Distribution and Control for Maneuverability and Stability of a 6WD Skid-Steering EUGV with Independent Drive Motors

In this paper, a hierarchical driving force distribution and control strategy for a six-wheel drive (6WD) skid-steering electric unmanned ground vehicle (EUGV) with independent drive motors is presented to improve the vehicle maneuverability and stability. The proposed hierarchical strategy is based on a nine-degrees-of-freedom (DOFs) dynamics model of 6WD skid-steering EUGV with a vehicle system dynamics model, wheel dynamics model, and tire model. In the proposed hierarchical strategy, the upper layer controller calculates the resultant driving force and yaw moment to control the vehicle motion states to track the desired ones by using the integral sliding mode control (ISMC) and proportion–integral–differential (PID) control methods. In the lower layer controllers, the driving force distribution method is adopted to allocate torques to the six motors. An objective function is proposed and composed of the longitudinal tire workload rates and weighting factors, considering the inequality constraints and equality constraints, which is solved by using the active set method. In order to evaluate the effectiveness of the proposed method, experiments with two types of scenarios were conducted. Comparative studies were also conducted with the other two methods used in the literature. The experimental results show that better performance can be achieved with the proposed control strategy in vehicle maneuverability and stability.

Integration of time information and temporal conformance graphics in map displays for navigation with space-time obligation

Design strategies on the display for navigation with multiple time obligations are developed and tested using a public bus application. The map display has a current time indicator and scheduled/estimated arrival time data at multiple bus stops. Two different time formats were applied to the time data at the bus stops: exact time at each stop and duration until them. Graphics symbols indicating earliness or lateness to ordinary scheduled time were also developed and tested. Under the four manipulated map types, experimenters asked participants eight different types of questions about space and/or time status. The experimenters then evaluated the response time and accuracy of produced answers. The response times were shorter or similar when the time formats corresponded questions. The workload rating and participants' feedback showed an advantage of duration format and the temporal conformance graphics.

Health assessment for railway switch systems

Because of the heavy workload and high failure rate of railway switch system (RSS), the traditional scheduled maintenance can not meet the actual operation needs of the railway. Therefore condition-based maintenance (CBM) and prognostic and health management(PHM), which have been mature in other fields should be introduced into RSS. Health assessment is of a great concern among all the technologies. This paper presents a novel method which can be utilized on the health status evaluation of RSS. First of all, RSS is briefly introduced and the connotation of PHM for RSS is analyzed. Secondly, health indicators (HIs) are extracted by different time domain features, and the best indicators are selected to establish the degradation model. By using clustering algorithm, the change point of state is detected which can be used as an instruction of advance maintenance. Finally, a ZYJ7 RSS is selected to test and verify the proposed method. Result indicates that the algorithm can be effectively applied to health assessment of RSS.

Developing a subjective instrument for laparoscopic surgical workload in a high fidelity simulator using the NASA-TLX and SURG-TLX

The Surgery Task Load Index (SURG-TLX) and National Aeronautics and Space Administration Task Load Index (NASA-TLX) are subjective workload assessment instruments. These instruments have three coinciding workload dimensions, but each has three unique dimensions. Each dimension is explained by a unique descriptor. It was hypothesized that the SURG-TLX and NASA-TLX workload ratings would differ when assessing the same surgical methods and tasks. Accordingly, the aim of this study was to assess the SURG- and NASA-TLX dimensions toward the creation of a novel workload instrument to better predict simulated laparoscopic surgical workload. Twenty-five (25) participants were selected at a large, midwestern teaching hospital to conduct two simulated surgical tasks using four different laparoscopic methods. Each participant completed a total of eight trials and after each trial workload was assessed using both the NASA-TLX and SURG-TLX. The overall NASA-TLX dimensions were rated significantly higher (greater workload) compared to the overall SURG-TLX dimensions (F = 12.04, p = 0.001). Principle component analysis of workload dimensions suggests that a new surgical subjective workload measurement instrument should include the dimensions of Mental Demand, Physical Demand, Temporal Demand, Performance, Frustration and Situational Stress. However, validation of this novel tool is needed.

An Evaluation of UAS Pilot Workload and Acceptability Ratings with Four Simulated Radar Declaration Ranges

Currently, minimum operational performance standards (MOPS) are being developed for a broader rangeof unmanned aircraft system (UAS) platforms, including smaller UAS that will feature onboard sensors that are low in size, weight, and power, otherwise known as low SWaP. The low SWaP sensors used to detect non-cooperative traffic will have limited declaration ranges compared to those designed for medium-to-large UAS. A human-in-the-loop (HITL) study was conducted examining four possible radar declaration ranges (i.e., 1.5 NM, 2 NM, 2.5 NM, and 3 NM) for a potential low SWaP sensor with a detect and avoid (DAA) system encountering various non-cooperative encounters in Oakland Center airspace. Participants had lower workload, particularly workload associated with temporal demand and effort, in scenarios that featured larger detection ranges. Furthermore, participants reported better ability to remain DAA well clear within the larger declaration range conditions, specifically with the 2.5 NM and 3 NM conditions.

The Effect of Task Complexity on Eye Movement and Multitasking Performance in Students With and Without ADHD

Attention Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder that affects many individual’s ability to maintain and shift attention. Little is known about the connection between executive function and eye movement in individuals diagnosed with ADHD during multitasking. The objective of this research is to examine the relationship between patterns of eye movement and multitasking performance between students with and without ADHD. During the experiment, students with and without ADHD completed NASA’s Multi-Attribute Task Battery at both low and high task complexity. We found that students without ADHD showed higher error counts, higher workload ratings, and greater total number of fixations in the high task complexity than in the low task complexity. By understanding the relationship among eye movement, executive functioning, and mental workload, it is possible to gain insight in attention allocation in online learning environments and apply that knowledge to create tools for equal access to learning.

Sensor-based indicators of performance changes between sessions during robotic surgery training

Training of surgeons is essential for safe and effective use of robotic surgery, yet current assessment tools for learning progression are limited. The objective of this study was to measure changes in trainees’ cognitive and behavioral states as they progressed in a robotic surgeon training curriculum at a medical institution. Seven surgical trainees in urology who had no formal robotic training experience participated in the simulation curriculum. They performed 12 robotic skills exercises with varying levels of difficulty repetitively in separate sessions. EEG (electroencephalogram) activity and eye movements were measured throughout to calculate three metrics: engagement index (indicator of task engagement), pupil diameter (indicator of mental workload) and gaze entropy (indicator of randomness in gaze pattern). Performance scores (completion of task goals) and mental workload ratings (NASA-Task Load Index) were collected after each exercise. Changes in performance scores between training sessions were calculated. Analysis of variance, repeated measures correlation, and machine learning classification were used to diagnose how cognitive and behavioral states associate with performance increases or decreases between sessions. The changes in performance were correlated with changes in engagement index (rrm=−.25,p<.001) and gaze entropy (rrm=−.37,p<.001). Changes in cognitive and behavioral states were able to predict training outcomes with 72.5% accuracy. Findings suggest that cognitive and behavioral metrics correlate with changes in performance between sessions. These measures can complement current feedback tools used by medical educators and learners for skills assessment in robotic surgery training.

Effects of Occupational Fatigue on Cognitive Performance of Staff From a Train Operating Company: A Field Study.

BackgroundOccupational fatigue is a key issue in the rail industry that can endanger staff, passenger, and train safety. There is a need to demonstrate the relationship between workload, fatigue, and performance among rail staff.ObjectiveThe present study, conducted in the workplace in realistic situations, integrating both subjective and objective measurements, aimed at demonstrating the relationship between workload, fatigue, and cognitive performance with a rail staff sample.MethodsThe “After-Effect” technique was applied in the current study. Online diaries and cognitive performance tasks were used to assess the fatigue, work experiences, and performance of rail staff before and after work on the first and last days of one working week.ResultsReported fatigue was greater after work on both the first and last day of the working week. There were large individual differences in the change in fatigue and workload ratings. Analysis of covariance with age and the pre-work performance score as covariates and the post-work performance score as the dependent variable showed that high levels of fatigue were associated with impaired performance on both the visual search and logical reasoning tasks. Workload had fewer effects on performance than fatigue.ConclusionThis field study provided evidence for the relationship between work-related fatigue and performance impairment. The findings show the need for future work on predicting fatigue-related performance decrements, and the necessity of providing interventions and support so that the risk to safety can be reduced.

A-111 The Relationship between Bilingualism and Perceived Workload on the Symbol Digit Modalities Test in Traumatic Brain Injury Survivors

Abstract Objective We evaluated perceived workload (measured by the NASA Task Load Index; NASA-TLX) as related to Symbol Digit Modalities Test (SDMT) performances in monolingual and bilingual traumatic brain injury (TBI) survivors and healthy comparison participants (HC). Method The sample consisted of 28 TBI survivors (12 monolinguals &amp; 16 bilinguals) and 50 HC (20 monolinguals &amp; 30 bilinguals). SDMT written (SDMT-W) and SDMT oral (SDMT-O) were used to evaluate group differences. Results ANCOVA, controlling for age, revealed that the HC group outperformed the TBI group on SDMT-W, p = .001, and SDMT-O, p = .047. Furthermore, bilinguals outperformed monolinguals on SDMT-W, p = .017. On the NASA-TLX, an interaction emerged on temporal demand rating, p = .023, with TBI bilinguals reporting higher temporal demand on SDMT tasks compared to TBI monolinguals, while the HC monolingual participants reported higher temporal demands ratings compared to HC bilingual participants. Furthermore, monolingual participants showed higher levels of frustration with regard to the SDMT task compared to bilingual participants, p = .029. Conclusion Our data revealed TBI survivors underperformed on both SDMT trials compared to the HC participants. Also, bilingual participants demonstrated better SDMT-W performances compared to monolingual participants. Furthermore, our TBI bilingual sample reported themselves to be more rushed to complete the SDMT compared to monolingual TBI sample, but they were less frustrated. Meanwhile, our HC monolingual sample felt more rushed to complete the SDMT tasks compared to HC bilingual participants, but they were less frustrated. While we observed differences in workload ratings between language groups, it is unclear if language use, and/or other variables are driving these results.

Predicting changes in performance due to cognitive fatigue: A multimodal approach based on speech motor coordination and electrodermal activity

Objective Military job and training activities place significant demands on service members’ (SMs’) cognitive resources, increasing risk of injury and degrading performance. Early detection of cognitive fatigue is essential to reduce risk and support optimal function. This paper describes a multimodal approach, based on changes in measures of speech motor coordination and electrodermal activity (EDA), for predicting changes in performance following sustained cognitive effort. Methods Twenty-nine active duty SMs completed computer-based cognitive tasks for 2 h (load period). Measures of speech derived from audio were acquired, along with concurrent measures of EDA, before and after the load period. Cognitive performance was assessed before and during the load period using the Automated Neuropsychological Assessment Metrics Military Battery (ANAM MIL). Subjective assessments of cognitive effort and alertness were obtained intermittently. Results Across the load period, participants’ ratings of cognitive workload increased, while alertness ratings declined. Cognitive performance declined significantly during the first half of the load period. Three speech and arousal features predicted cognitive performance changes during this period with statistically significant accuracy: EDA (r = 0.43, p = 0.01), articulator velocity coordination (r = 0.50, p = 0.00), and vocal creak (r = 0.35, p = 0.03). Fusing predictions from these features predicted performance changes with r = 0.68 (p = 0.00). Conclusions Results suggest that speech and arousal measures may be used to predict changes in performance associated with cognitive fatigue. This work supports ongoing efforts to develop reliable, unobtrusive measures for cognitive state assessment aimed at reducing injury risk, informing return to work decisions, and supporting diverse mobile healthcare applications in civilian and military settings.

Recovery from work: testing the effects of chronic internal and external workload on health and well-being

BackgroundThe aim of this study was to examine the effects of reduced recovery opportunities on health, associated with chronic internal workload (ie, during work) and external workload (ie, following work).MethodsData...