EEG-based cognitive load estimation during the use of a virtual wheelchair simulator

Ensuring human safety has been one of the most critical considerations within the field of human–robot interaction. To explore the effects of working with autonomous robots on human coworkers’ perceived workload and job performance, two experiments were conducted in this study. Eight participants were recruited in the first experiment. Results revealed an increase in both subjective and objective workload measurements: compared to the baseline “no robot” to “empty payload” condition, the sum of NASA Task Load Index (NASA-TLX) scores increased from 129.3 (58.8) to 147.6 (53.7) ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$p$</tex-math></inline-formula> -value = 0.041) and the pupil diameter increased from 4.07 (0.64) mm to 4.11 (0.67) mm; while working with a full payload robot, the sum of NASA-TLX scores increased to 151.7 (55.9) ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$p$</tex-math></inline-formula> -value = 0.010) and the pupil diameter increased to 4.12 (0.66) mm. Increased task completion time (3.1% for empty payload condition and 6.6% for full payload condition) showed a decrease in human productivity. However, this slight human output reduction was compensated by the substantial gain from the robot. Similar effects of autonomous mobile robots on participants’ NASA-TLX scores and task completion time were observed in the second experiment, where eight participants performed the order picking and sorting tasks in a high-fidelity grocery store setting. Results from the study suggested the feasibility of applying fully autonomous mobile robots in Wholesale and Retail Trade settings to improve human–robot team productivity while prioritizing physical safety and reasonable increases in mental workload.

Impact of Mobile Device-Based Clinical Decision Support Tool on Guideline Adherence and Mental Workload

Driving a wheelchair is difficult and complex, where it requires motor, visual and cognitive skills. There are simulators aimed mainly at users without or with little experience of using this assistive technology as a form of safe training. However, the real wheelchair and the simulator need to be developed or improved so that the users feel adapted and motivated to use them. Developing technologies to assist people without using assessments that help to understand and bring users closer to developers leads to giving up and discouraging the use of these tools. Many of these assessments are made using subjective metrics, such as interviews or questionnaires; and objective metrics are often related to user performance. Generally, these subjective metrics are classified as explicit, which are the responses that the user is aware of. These metrics can often not reflect people’s genuine opinions and feelings. In contrast, implicit measures infer mental content based on tasks, that can be evaluated continuously while the task is being performed. In this perspective, the present work aimed to assess the cognitive load during the use of the virtual reality training tool, the wheelchair simulator. The study proposes the use of implicit metrics, specifically, the blink indexes derived from an EEG signal. In summary, the study analysed implicit and explicit metrics of a task performed in the wheelchair simulator in a virtual environment. The explicit metrics were derived from questionnaires on usability, presence, cognitive load and performance. The implicit metrics, on the other hand, were the characteristics of the frequency, duration and velocity of the blinks collected during the experiment. The results were consistent with the reports found in the literature, where, the cognitive load that requires a mental-visual demand is related to the decrease in the frequency, duration and velocity of the blink. The results of the correlation analyses between the NASA-TLX scores (subjective cognitive load assessment) and the blink parameters were moderate and weak. Thus, at the moment, for the application presented, it is concluded that evaluating only the blinks is not enough to infer the cognitive load, however it is a metric that applied in conjunction with questionnaires can show more relevant information than just the application of questionnaires.

The contrast of a website doesn’t just affect its usability for low-vision individuals; it affects everyone. This study aims to evaluate the effects of contrast (low, medium, or high) on web browsing experience in normally-sighted individuals. Cognitive load associated with the task was assessed using the NASA task load index (NASA-TLX) and the usability of the website was assessed by the systems usability scale (SUS). We found that NASA-TLX scores significantly increased with the amount of time a task took, indicating an effect of task difficulty. The impact of contrast was reported during end-of-study interviews, but no significant difference was found between the three chosen contrast levels in NASA-TLX or SUS scores. This study is part 1 of a multi-part research project and future research will compare low-vision individuals to their typically-sighted peers. Together, the studies in this project aim to quantitatively determine the effects of contrast users’ web browsing experience to further accessibility research and web development guidelines.

Objective:The NASA Task Load Index is a questionnaire widely used in aviation. This index might help for attesting the quality of a scenario in high-fidelity simulation in healthcare. The main purpose of this study was to observe whether NASA Task Load Index for critical care-simulated scenarios, designed for residents, was consistent with the literature. The second purpose was to describe relationships between NASA Task Load Index, performance and generated stress during high-fidelity simulation.Methods:All residents in anaesthesia and intensive care undergoing high-fidelity simulation were included. The primary endpoint was the task load generated by each scenario assessed by NASA Task Load Index. Based on the literature, the NASA Task Load Index scores between 39 and 61 were considered an acceptable level. Stress level (Visual Analogue Scale) and specific technical and non-technical skills performances (Team Emergency Assessment Measure) were also assessed.Results:Totally 53 residents actively participated in 1 of 10 different scenarios, between June and December 2017. The median NASA Task Load Index score of scenarios was 61 [48-65]. Five scenarios generated acceptable task load levels. There was no association between the NASA Task Load Index score and technical or non-technical skills performance scores, but an association between NASA Task Load Index and the stress level (rho = 4.7, P = .001) was observed.Conclusion:Simulation scenarios generate different task loads for residents; the task load was deemed acceptable for half of the scenarios. The NASA Task Load Index could be considered as a tool to assess the pedagogic adequacy of scenarios. Scenario and generated stress level, but not task load, can modify residents’ performance during simulation. This should be considered when planning normative simulation.

BackgroundCognitive load impacts performance of debriefers and learners during simulations, but limited data exists examining debriefer cognitive load. The aim of this study is to compare the cognitive load of the debriefers during simulation-based team training (SbTT) with Rapid Cycle Deliberate Practice (RCDP) debriefing and Traditional Reflective Debriefing (TRD). We hypothesize that cognitive load will be reduced during RCDP compared to TRD.MethodsThis study was part of a large-scale, interdisciplinary team training program at Children’s Healthcare of Atlanta Egleston Pediatric Emergency Department, with 164 learners (physicians, nurses, medical technicians, paramedics, and respiratory therapists (RTs)). Eight debriefers (main facilitators and discipline-specific coaches) led 28 workshops, which were quasi-randomized to either RCDP or TRD. Each session began with a baseline medical resuscitation scenario and cognitive load measurement using the NASA Task Load Index (TLX), and the NASA TLX was repeated immediately following either TRD or RCDP debriefing. Raw scores of the NASA TLX before and after intervention were compared. ANOVA tests were used to compare differences in NASA TLX scores before and after intervention between the RCDP and TRD groups.ResultsFor all debriefers, mean NASA TLX scores for physical demands and frustration significantly decreased (− 0.8, p = 0.004 and − 1.3, p = 0.002) in TRD and mean perceived performance success significantly increased (+ 2.4, p < 0.001). For RCDP, perceived performance success increased post-debriefing (+ 3.6, p < 0.001), time demands decreased (− 1.0, p = 0.04), and frustration decreased (− 2.0, p < 0.001). Comparing TRD directly to RCDP, perceived performance success was greater in RCDP than TRD (3.6 vs. 2.4, p = 0.04). Main facilitators had lower effort and mental demand in RCDP and greater perceived success (p < 0.001).ConclusionRCDP had greater perceived success than TRD for debriefers. Main facilitators also report reduced effort and baseline mental demand in RCDP. For less experienced debriefers, newer simulation programs, or large team training sessions such as our study, RCDP may be a less mentally demanding debriefing methodology for facilitators.

Evaluation of workplace ergonomics for office workers is significant for occupational health. Since office employees’ work is often mental, this evaluation should include a mental work-load assessment as well as a physical assessment. The purpose of this study is to examine the physical and mental workload of office workers of an automotive supplier company. This study was carried out on 250 office workers. The musculoskeletal and physical risks were investigated using Rapid Office Strain Assessment (ROSA) and Cornell Musculoskeletal Discomfort Questionnaire (CMDQ), and the mental workload was analyzed with NASA Task Load Index (NASA-TLX). Musculoskeletal disorder risk and mental workload levels were revealed by statistical analysis and examined on the basis of departments. The correlations between risk levels obtained by different methods and the effect of gender and age factors were also investigated. ROSA final score average was 3.69 which corresponds to a moderate risk level. 62.4% of the employees for the chair section and 64.4% of them for the keyboard and mouse section were at moderate and above risk levels. According to the CMDQ results, the body regions with the most discomfort were determined as the neck, upper back, lower back and right wrist. NASA-TLX scores showed that the highest mental workload occurs in office workers in Accounting, Maintenance and Purchasing departments. NASA-TLX scores were found to be correlated with the ROSA final score, but not with the CMDQ scores. Evaluating the musculoskeletal disorder risks and mental workload of office workers together and taking the necessary precautions were beneficial in terms of protecting the health of the employees.

This study investigates the relationship between cognitive load and explicitation strategies employed by trainee interpreters during sight interpreting/translation (SiT). Using a mixed-methods approach, the study analysed interpreting outputs, retrospective verbal reports, interviews and self-assessments using the NASA Task Load Index (TLX). It explores how variations in task-induced cognitive load influence explicitating behaviour of trainee interpreters. The main research questions address (1) the correlation between cognitive load and explicitation frequency, and (2) the impact of varying load conditions on the nature of explicitating shifts. Eleven interpreting trainees performed SiT tasks with two texts of differing readability, designed to elicit high (T1) and low (T2) cognitive load. Quantitative analysis revealed moderate but statistically significant correlations between explicitations and both disfluency frequency and NASA TLX scores. Qualitative findings indicated that under high cognitive load (T1), explicitation served primarily as a coping mechanism to manage lexical or structural challenges. In contrast, under lower load (T2), explicitation was used more strategically to enhance textual cohesion and clarity. These findings highlight the dual function of explicitation: as a coping, process-oriented strategy under cognitive strain, and as a product- and audience-oriented tool when cognitive resources are less taxed, offering insights for interpreter training and cognitive processing research.

Operators in high-stress environments often face significant cognitive demands that can impair their performance, underscoring the need for comprehensive workload assessment. This study aims to study the relationship between subjective self-reported measures, the NASA task load index (NASA-TLX), objective bio-signal measures, and pupillary responses. The participants engaged in either a visual tracking task or a laparoscopic visuomotor task while their eye movements were recorded using a Tobii Pro Nano eye tracker (Tobii Technology Inc., Stockholm, Sweden). Immediately after completing the tasks, participants provided NASA-TLX scores to assess their perceived workload. The study tested three hypotheses: first, whether increased pupil dilation correlates with higher NASA-TLX scores; second, whether task type affects workload; and third, whether task repetition influences workload. The results showed a moderate positive correlation between pupil size and NASA-TLX scores (r = 0.513, p &lt; 0.001). The laparoscopic surgery task, which requires visuomotor coordination, resulted in significantly higher NASA-TLX scores (t = –6.23, p &lt; 0.001), larger original pupil sizes (t = –22.57, p &lt; 0.001), and more adjusted pupil sizes (t = –22.57, p &lt; 0.001) than the purely visual task. Additionally, task repetition led to a significant reduction in the NASA-TLX scores (t = 2.86, p = 0.005), the original mean pupil size (t = 5.50, p &lt; 0.001), and the adjusted pupil size (t = 6.34, p &lt; 0.001). In conclusion, the study confirms a positive correlation between NASA-TLX scores and pupillary responses. Task type and repetition were found to influence workload and pupillary responses. The findings demonstrate the value of using both subjective and objective measures for workload assessments.

Assessment of surgeon workload using the NASA-TLX during the early introduction of robot-assisted total knee arthroplasty.

BackgroundCAD (Computer Aided Design) designers spend long hours in front of visual displays, using specialized automotive design software. In addition to musculoskeletal disorders that may result from prolonged static activities, these individuals are also exposed to high mental workloads.ObjectiveThis study aims to assess the effect of office strain levels on the mental workload and musculoskeletal disorders of the design department.MethodsThis descriptive-analytical study included 48 cases, consisting of the occupation of CAD designing from the computer design department, and 48 control participants, comprised of non-computer users. It assessed musculoskeletal disorders using the CMDQ (Cornell Musculoskeletal Discomfort Questionnaire), ergonomic risk with the ROSA (Rapid Office Strain Assessment), and mental workload with the NASA-TLX (NASA Task Load Index). Data were analyzed using SPSS version 22.ResultsIn the case group, 37.5% were categorized as high risk for strain, compared to 31.25% in the control group. 27.08% of participants experienced an unacceptable level of mental workload according to NASA-TLX criteria, while only 17.71% were within the acceptable level. Significant relationships were found between office strain, musculoskeletal disorders, and mental workload, with a direct correlation between ROSA, NASA-TLX, and CMDQ scores (<0.011).ConclusionsThe most significant factors influencing office strain and mental workload among the occupation of CAD designing include ergonomic conditions in the workplace, duration of computer use, temporal demand, and the nature of job tasks. Factors such as health status, physical characteristics, and work experience are crucial in determining the intensity of mental workload and office strain.

Measuring the Impact of an Exoscopic Camera System on Learner Mental Workload in Vaginal Surgery.

ObjectivesTo develop a wet laboratory training model for learning core laparoscopic surgical skills and evaluating learners’ competency level outside the operating room.MethodsParticipants completed three tasks (task 1: tissue dissection around the aorta; task 2: tissue dissection and division of the renal artery; task 3: renal parenchymal closure). Each performance was video recorded and subsequently evaluated by two experts, according to the Global Operative Assessment of Laparoscopic Skills and task‐specific metrics that we developed (Assessment Sheet of Laparoscopic Skills in Wet Lab score). Mean scores were used for analyses. The subjective mental workload was also assessed (NASA Task Load Index).ResultsThe 54 participants included 32 urologists, eight young trainees and 14 medical students. A total of 13 participants were categorized as experts (≥50 laparoscopic surgeries), eight as intermediates (10–49) and 33 as novices (0–9). There were significant differences in the Global Operative Assessment of Laparoscopic Skills and Assessment Sheet of Laparoscopic Skills in Wet Lab scores among the three groups in all three tasks. Higher NASA Task Load Index scores were observed in novices, and there were significant differences in tasks 1 (Kruskal–Wallis test, P = 0.0004) and 2 (P = 0.0002), and marginal differences in task 3 (P = 0.0745) among the three groups.ConclusionsOur training model has good construct validity, and differences in the NASA Task Load Index score reflect previous laparoscopic surgical experiences. Our findings show the ability to assess both laparoscopic surgical skills and mental workloads, which could help educators comprehend trainees’ level outside the operating room. Given the decreasing opportunity to carry out pure laparoscopic surgeries because of the dissemination of robotic surgery, especially in urology, our model can offer practical training opportunities.

Dual process models posit that combinations of impulsive and reflective processes drive behaviour, and that the capacity to engage in effortful cognitive processing moderates the relation between measures of impulsive or reflective processes and actual behaviour. When cognitive resources are low, impulsive processes are more likely to drive behaviour, while when cognitive resources are high, reflective processes will drive behaviour. In our current study, we directly addressed this hypothesis by comparing the capacity of implicit and explicit measures to predict fear and anxiety, either with or without additional cognitive load. In Experiment 1 (N = 83), only explicit measures of spider fear were predictive of spider avoidance, and manipulating cognitive load did not affect these relations. Experiment 2 (N = 70) confirmed these findings, as the capacity of explicit and implicit measures to predict self-reported and physiological responses to a social stressor was not moderated by cognitive load. In two experiments, we thus found no empirical support for the central dual process model assumption that cognitive control moderates the predictive value of implicit and explicit measures. While implicit measures and dual process accounts may still be valuable, we show that results in this field are not necessarily replicable and inconsistent.

ObjectivesUntil now, there have been few tools to evaluate whether a surgeon was technically ready to perform a safe pancreaticojejunostomy (PJ). In the current study, we aimed to evaluate whether...