Quantifying the cognitive cost of laparo-endoscopic single-site surgeries: Gaze-based indices

Strain on the surgeon: a systematic review of the methods of measuring strain in abdominal and thoracic surgery

INTRODUCTION

Surgery can be arduous to the operating surgeon - both in terms of cognitive and physical strain. Ergonomic strain has been recognised to drive absenteeism, reduce career longevity and cause injuries. This systematic review aims to 1. Outline the nature of ergonomic strain in the context of abdominal and thoracic surgery, regardless of surgical approach 2. Identify the qualitative and quantitative measures of surgical strain.

METHODS

A systematic review was conducted using Pubmed, MEDLINE and Ovid EMBASE databases (date range: 1990 to Sep 2024). Of the initial 1288 articles identified, a final 71 studies were included in this review (quantitative measures = 36, qualitative measures = 49, of which 14 studies overlapped with the papers reviewed in the quantitative measures section).

RESULTS

The quantitative measures used to measure ergonomic strain included electromyography, electrocardiography, gravimetric position sensors, skin conductance and inertial measurement units. Laparoscopic surgery caused less physical strain than open surgery, however more cognitive strain during the learning curve. Robotic surgery yielded conflicting data in terms of muscle activation when compared to laparoscopic surgery however reported less cognitive and cardiovascular strain. The qualitative measures of strain included a range of self-reported questionnaires, demonstrating important gender differences and scores that typically correlated with objective physical strain.

DISCUSSION

The studies show wide variation in measuring ergonomic strain. Avenues for further research include measuring the impact of learning curves, patient factors on ergonomic strain and the impact of gender.

Gaze entropy metrics for mental workload estimation are heterogenous during hands-off level 2 automation

As the level of vehicle automation increases, drivers are more likely to engage in non-driving related tasks which take their hands, eyes, and/or mind away from the driving task. Consequently, there has been increased interest in creating Driver Monitoring Systems (DMS) that are valid and reliable for detecting elements of driver state. Workload is one element of driver state that has remained elusive within the literature. Whilst there has been promising work in estimating mental workload using gaze-based metrics, the literature has placed too much emphasis on point estimate differences. Whilst these are useful for establishing whether effects exist, they ignore the inherent variability within individuals and between different drivers. The current work builds on this by using a Bayesian distributional modelling approach to quantify the within and between participants variability in Information Theoretical gaze metrics. Drivers (N = 38) undertook two experimental drives in hands-off Level 2 automation with their hands and feet away from operational controls. During both drives, their priority was to monitor the road before a critical takeover. During one drive participants had to complete a secondary cognitive task (2-back) during the hands-off Level 2 automation. Changes in Stationary Gaze Entropy and Gaze Transition Entropy were assessed for conditions with and without the 2-back to investigate whether consistent differences between workload conditions could be found across the sample. Stationary Gaze Entropy proved a reliable indicator of mental workload; 92 % of the population were predicted to show a decrease when completing 2-back during hands-off Level 2 automated driving. Conversely, Gaze Transition Entropy showed substantial heterogeneity; only 66 % of the population were predicted to have similar decreases. Furthermore, age was a strong predictor of the heterogeneity of the average causal effect that high mental workload had on eye movements. These results indicate that, whilst certain elements of Information Theoretic metrics can be used to estimate mental workload by DMS, future research needs to focus on the heterogeneity of these processes. Understanding this heterogeneity has important implications toward the design of future DMS and thus the safety of drivers using automated vehicle functions. It must be ensured that metrics used to detect mental workload are valid (accurately detecting a particular driver state) as well as reliable (consistently detecting this driver state across a population).

Cognitive effort detection for tele-robotic surgery via personalized pupil response modeling

PURPOSE

Gaze tracking and pupillometry are established proxies for cognitive load, giving insights into a user's mental effort. In tele-robotic surgery, knowing a user's cognitive load can inspire novel human-machine interaction designs, fostering contextual surgical assistance systems and personalized training programs. While pupillometry-based methods for estimating cognitive effort have been proposed, their application in surgery is limited by the pupil's sensitivity to brightness changes, which can mask pupil's response to cognitive load. Thus, methods considering pupil and brightness conditions are essential for detecting cognitive effort in unconstrained scenarios.

METHODS

To contend with this challenge, we introduce a personalized pupil response model integrating pupil and brightness-based features. Discrepancies between predicted and measured pupil diameter indicate dilations due to non-brightness-related sources, i.e., cognitive effort. Combined with gaze entropy, it can detect cognitive load using a random forest classifier. To test our model, we perform a user study with the da Vinci Research Kit, where 17 users perform pick-and-place tasks in addition to auditory tasks known to generate cognitive effort responses.

RESULTS

We compare our method to two baselines (BCPD and CPD), demonstrating favorable performance in varying brightness conditions. Our method achieves an average true positive rate of 0.78, outperforming the baselines (0.57 and 0.64).

CONCLUSION

We present a personalized brightness-aware model for cognitive effort detection able to operate under unconstrained brightness conditions, comparing favorably to competing approaches, contributing to the advancement of cognitive effort detection in tele-robotic surgery. Future work will consider alternative learning strategies, handling the difficult positive-unlabeled scenario in user studies, where only some positive and no negative events are reliably known.

A Framework for the Evaluation of Human Machine Interfaces of Robot-Assisted Colonoscopy

The Human Machine Interface (HMI) of intraluminal robots has a crucial impact on the clinician's performance. It increases or decreases the difficulty of the tasks, and is connected to the users' physical and mental stress.

OBJECTIVE

This article presents a framework to compare and evaluate different HMIs for robotic colonoscopy, with the objective of identifying the optimal HMI that minimises the clinician's effort and maximises the clinical outcomes.

METHODS

The framework comprises a 1) a virtual simulator (clinically validated), 2) wearable sensors measuring the cognitive load, 3) a data collection unit of metrics correlated to the clinical performance, and 4) questionnaires exploring the users' impressions and perceived stress. The framework was tested with 42 clinicians investigating the optimal device for tele-operated control of robotic colonoscopes. Two control devices were selected and compared: a haptic serial-kinematic device and a standard videogame joypad.

RESULTS

The haptic device was preferred by the endoscopists, but the joypad enabled better clinical performance and reduced cognitive and physical load.

CONCLUSION

The framework can be used to evaluate different aspects of a HMI, both hardware and software, and determine the optimal HMI that can reduce the burden on clinicians while improving the clinical outcome.

SIGNIFICANCE

The findings of this study, and of future studies performed with this framework, can inform the design and development of HMIs for intraluminal robots, leading to improved clinical performance, reduced physical and mental stress for clinicians, and ultimately better patient outcomes.

Eye-tracking in surgery: a systematic review

BACKGROUND

Surgery is constantly evolving with the assistance of rapidly developing novel technology. Eye-tracking devices provide opportunities to monitor the acquisition of surgical skills, gain insight into performance, and enhance surgical practice. The aim of this review was to consolidate the available evidence for the use of eye-tracking in the surgical disciplines.

METHODS

A systematic literature review was conducted in accordance with PRISMA guidelines. A search of OVID Medline, EMBASE, Cochrane library, Scopus, and Science Direct was conducted January 2000 until December 2022. Studies involving eye-tracking in surgical training, assessment and technical innovation were included in the review. Non-surgical procedures, animal studies, and studies not involving surgical participants were excluded from the review.

RESULTS

The search returned a total of 12 054 articles, 80 of which were included in the final analysis and review. Seventeen studies involved eye-tracking in surgical training, 48 surgical assessment, and 20 were focussing on technical aspects of this technology. Twenty-six different eye-tracking devices were used in the included studies. Metrics such as the number of fixations, duration of fixations, dwell time, and cognitive workload were able to differentiate between novice and expert performance. Eight studies demonstrated the effectiveness of gaze-training for improving surgical skill.

CONCLUSION

The current literature shows a broad range of utility for a variety of eye-tracking devices in surgery. There remains a lack of standardization for metric parameters and gaze analysis techniques. Further research is required to validate its use to establish reliability and create uniform practices.

Ergonomic learning curves on gynecological laparoendoscopic single-site (LESS) surgery

BACKGROUND

Few previous studies have introduced general techniques to overcome the "chopstick effect" in laparoendoscopic single-site surgery (LESS). We aim to investigate and highlight the key ergonomic methodologies for gynaecologic LESS based on the surgeon's hands-on performance.

METHODS

The first author surgeon A reviewed and analyzed the LESS procedures performed by herself and how she taught surgeon B from January 2021 to April 2022. The procedures were classified based on technical difficulty and learning periods, and the hands-on technical skills of LESS module were evaluated.

RESULTS

Surgeon A conducted 580 LESS procedures, which were divided into the novice (n = 48) and intermediate (n = 33) periods, and the remaining cases were included in the routine period. We formed a special ergonomic LESS operating methodology: Maintain good LESS laparoscopic spatial sensation, keep hand-eye coordination, well cooperation between the main surgeon and the assistant; Experienced multiport laparoscopy surgery (MPS) skills, improve basic LESS technique: grasp, lift, transfer, place, blunt separating, coagulation and cutting. Coordination location, orientation, movements, and flexion or extension of shoulders, arms, elbow, wrist and finger joints; Maintain strength, tension and ambidexterity postures with joint and muscular efforts to control instruments. Surgeon B learned the above experiences by performing 39 LESS procedures under the guidance of surgeon A.

CONCLUSION

This educational research sheds light on the common challenges faced in LESS and presents the importance of ergonomic hands-on performance skills in improving surgical outcomes, which could serve as a guide for future training and education in LESS.

Technical, ergonomic and cognitive learning methodology in transumbilical single-port laparoscopic hysterectomy

OBJECTIVE

We introduced learning curves on a detailed step protocol and ergonomic aspect to determine key surgical points in transumbilical single-port laparoscopic hysterectomy (TSPLH) and to popularize both technical and cognitive methodology on laparoendoscopic single-site surgery (LESS).

MATERIALS AND METHODS

A retrospective analysis of 87 TSPLH procedures was conducted by a single surgeon in three learning stages. Technical, ergonomic, and cognitive steps were introduced, and surgical outcomes were analyzed.

RESULTS

Key production points in TSPLH include developing a clear retroperitoneal space, maintaining appropriate strength and direction with a vaginal manipulator, coagulating the uterine artery, and applying an improved vaginal stump suturing method. Technical factors included instrument domination, hand-eye coordination, and alternating hand functions. Ergonomic techniques focused on shoulder, elbow, arm, wrist, and finger movements, range of motion, muscle power, continuous forces, and flexibility. Improved cognitive factors such as confidence, decision-making, and communication were also observed.

CONCLUSIONS

The study aimed to form methodological education on TSPLH and LESS and benefit more surgeons. The detailed production and key ergonomic points will help guide self-learning and education.

Measurement and Management of Cognitive Load in Surgical Education: A Narrative Review

BACKGROUND

Cognitive load should be considered in designing optimal educational programs in health care. Despite the highly demanding nature of surgery and surgical education, a consensus on how to manage cognitive load has not been established. The objective of this review is to map out how recent surgical education research incorporates cognitive load.

METHODS

A literature search was performed using keywords related to cognitive load and digital education up to December 2021. Studies published in English relevant to assessment and management of cognitive load in surgical education were included. Terminology, assessment tools, association with different surgical procedures and training modalities, and programs considering cognitive load were reported.

RESULTS

We identified several terms to describe cognitive load. Cognitive load was measured by subjective, self-reported questionnaires and by objective measurements, such as physiological parameters or estimated by reaction time to secondary tasks. Subjective measurements reported cognitive load in one or multiple dimensions. Correlations between subjective and objective measurements were shown in multiple studies. Overall, higher cognitive load was observed in training for more complex tasks and high-fidelity modalities, and among less experienced trainees. Cognitive load theory has been lately incorporated into designing teaching programs.

CONCLUSIONS

A broad range of terms and assessment tools were identified for cognitive load. To maximize the learning outcome, management of cognitive load is necessary in surgical education. This review summarizes the current knowledge in assessment and management of cognitive load in surgical education and provides suggestions for future studies.

The Measurement of Cognitive Workload in Surgery Using Pupil Metrics: A Systematic Review and Narrative Analysis

INTRODUCTION

Increased cognitive workload (CWL) is a well-established entity that can impair surgical performance and increase the likelihood of surgical error. The use of pupil and gaze tracking data is increasingly being used to measure CWL objectively in surgery. The aim of this review is to summarize and synthesize the existing evidence that surrounds this.

METHODS

A systematic review was undertaken in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A search of OVID MEDLINE, IEEE Xplore, Web of Science, Google Scholar, APA PsychINFO, and EMBASE was conducted for articles published in English between 1990 and January 2021. In total, 6791 articles were screened and 32 full-text articles were selected based on the inclusion criteria. A narrative analysis was undertaken in view of the heterogeneity of studies.

RESULTS

Seventy-eight percent of selected studies were deemed high quality. The most frequent surgical environment and task studied was surgical simulation (75%) and performance of laparoscopic skills (56%) respectively. The results demonstrated that the current literature can be broadly categorized into pupil, blink, and gaze metrics used in the assessment of CWL. These can be further categorized according to their use in the context of CWL: (1) direct measurement of CWL (n = 16), (2) determination of expertise level (n = 14), and (3) predictors of performance (n = 2).

CONCLUSIONS

Eye-tracking data provide a wealth of information; however, there is marked study heterogeneity. Pupil diameter and gaze entropy demonstrate promise in CWL assessment. Future work will entail the use of artificial intelligence in the form of deep learning and the use of a multisensor platform to accurately measure CWL.

Eye Tracking Use in Surgical Research: A Systematic Review

INTRODUCTION

Eye tracking (ET) is a popular tool to study what factors affect the visual behaviour of surgical team members. To our knowledge, there have been no reviews to date that evaluate the broad use of ET in surgical research. This review aims to identify and assess the quality of this evidence, to synthesize how ET can be used to inform surgical practice, and to provide recommendations to improve future ET surgical studies.

METHODS

In line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic literature review was conducted. An electronic search was performed in MEDLINE, Cochrane Central, Embase, and Web of Science databases up to September 2020. Included studies used ET to measure the visual behaviour of members of the surgical team during surgery or surgical tasks. The included studies were assessed by two independent reviewers.

RESULTS

A total of 7614 studies were identified, and 111 were included for data extraction. Eleven applications were identified; the four most common were skill assessment (41%), visual attention assessment (22%), workload measurement (17%), and skills training (10%). A summary was provided of the various ways ET could be used to inform surgical practice, and three areas were identified for the improvement of future ET studies in surgery.

CONCLUSIONS

This review provided a comprehensive summary of the various applications of ET in surgery and how ET could be used to inform surgical practice, including how to use ET to improve surgical education. The information provided in this review can also aid in the design and conduct of future ET surgical studies.

Eye-Tracking Indicators of Workload in Surgery: A Systematic Review

BackgroundEye tracking is a powerful tool for unobtrusive and real time assessment of workload in clinical settings. Before the complex eye tracking derived surrogates can be proactively utilized to improve surgical safety, the indications, validity and reliability requires careful evaluation.MethodsWe conducted a systematic review of literature from 2010 to 2020 according to PRISMA guidelines. A search on PubMed, Cochrane, Scopus, Web of science, PsycInfo and Google scholar databases was conducted on July 2020. The following search query was used" ("eye tracking" OR "gaze tracking") AND (surgery OR surgical OR operative OR intraoperative) AND (workload OR stress)". Short papers, no peer reviewed or papers in which eye-tracking methodology was not used to investigate workload or stress factors in surgery, were omitted.ResultsA total of 17 (N = 17) studies were identified eligible to this review. Most of the studies (n = 15) measured workload in simulated setting. Task difficulty and expertise were the most studied factors. Studies consistently showed surgeon's eye movements such as pupil responses, gaze patterns, blinks were associated with the level of perceived workload. However, differences between measurements in operational room and simulated environments have been found.ConclusionPupil responses, blink rate and gaze indices are valid indicators of workload. However, the effect of distractions and non-technical factors on workload is underrepresented aspect in the literature even though recognized as underlying factors in successful surgery.

Years of experience is more effective in defining experts in the gaze analysis of laparoscopic suturing task than task duration

In this study, the relationship between gaze patterns, task duration, and years of experience, which are commonly used to define and evaluate expert surgeons in laparoscopic surgery, was identified. Ten surgeons with 1-28 years of experience and six inexperienced students were included. Subjects used forceps to repeat the task of suturing a suture pad. Each subject wore an eye-marking recorder, and gaze points were recorded and analyzed. No significant relationship between task duration and gaze pattern was observed. However, there was a significant relationship between a surgeon's years of experience and the percentage of time spent gazing at the forceps. Subjects with more years of experience operated without looking at the forceps and fixed their gaze on the operational target. Therefore, when analyzing laparoscopic gazing patterns, it may be more appropriate to define an "expert" based on the years of experience rather than task duration.

See Like an Expert: Gaze-Augmented Training Enhances Skill Acquisition in a Virtual Reality Robotic Suturing Task

Introduction: The da Vinci Skills Simulator (DVSS) is an effective platform for robotic skills training. Novel training methods using expert gaze patterns to guide trainees have demonstrated superiority to traditional instruction. Portable head-mounted eye-trackers (HMET) offer the opportunity for eye tracking technology to enhance surgical robotic simulation training. Objective: To evaluate if training guided by expert gaze patterns can improve trainee performance over standard movement training techniques during robotic simulation. Methods: Medical students were recruited and randomized into gaze training (GT, n = 9) and movement training (MT, n = 8) groups. First, the participants reviewed an instructional video, with the GT group emulating expert gaze patterns and the MT group (n = 8) standard movement-based instruction. Training consisted of 10 repetitions of "Suture Sponge 3" on the DVSS while wearing HMET; the first three repetitions were followed by group-appropriate video coaching (gaze vs movement feedback), while the remaining repetitions were without feedback. Finally, two multitasking repetitions with a secondary bell-counting task were completed. Primary outcomes included DVSS scores during training and multitasking. Secondary outcomes included metrics collected from the HMET (gaze patterns and gaze entropy). Results: Total score, efficiency, and penalties improved significantly over the training in both groups; the GT group achieved higher scores on every attempt. Total scores in the GT group were higher than the MT group postvideo review (20.3 ± 21.8 vs 3.0 ± 6.2, p = 0.047), after coaching repetitions (61.8 ± 18.8 vs 30.1 ± 26.2, p = 0.01), and at the last training attempt (73.0 ± 16.5 vs 63.1 ± 17.4, p = 0.247). During multitasking, the GT group maintained higher total scores (75 ± 10.1 vs 63.3 ± 15.3, p = 0.01), efficiency (86.3 ± 7.4 vs 77.4 ± 11.2, p = 0.009), and superior secondary task performance (error: 6.3% ± 0.06 vs 10.7% ± 0.11, p = 0.20). Gaze entropy (cognitive-load indicator) and gaze pattern analysis showed similar trends. Conclusion: Gaze-augmented training leads to more efficient movements through adoption of expert gaze patterns that withstand additional stressors.

The Learning Curve of Laparoendoscopic Single-Site Surgery in Benign Gynecological Diseases

OBJECTIVE

To analyze and draw the learning curve of laparoendoscopic single-site surgery (LESS) in various benign gynecological diseases, so as to provide a reference for applying this cutting-edge technique.

METHODS

A retrospective analysis of LESS was conducted. Factors influencing the LESS learning process were assessed using Cox's proportional hazards regression. The cumulative sum (CUSUM) value and the learning curve were calculated and visualized based on operation time (OT), blood loss (BL), conventional laparoscopic surgery (CLS), conversion rate (CV), and complications (CP). The CUSUM value was defined as the sum of CUSUM_OT, CUSUM_BL, CUSUM_CV, and CUSUM_CP.

RESULTS

A total of 445 cases, including adnexectomies (n = 147), ovarian cystectomies (n = 175), and myomectomies (n = 123) were analyzed. Multivariate regression analysis indicated that adhesion grade (HR, 1.462; 95% CI, 1.016-1.994; p = .045), surgical type (HR, 1.283; 95% CI, 1.042-1.429; p = .024), and surgeon CLS experience (HR, 1.372; 95% CI, 1.097-2.246; p = .012) were independent factors predicting surgeons' mastery of the LESS technique. Among gynecologists with CLS experience, the cutoff points were 17, 20, and 27 cases for adnexectomy, ovarian cystectomy, and myomectomy, respectively. For those without CLS experience, the corresponding cutoff values were 19, 27, and 35 cases.

CONCLUSION

The learning curve of LESS for benign gynecological diseases indicates a stepwise process, during which the surgeon's CLS experience is the key, especially in ovarian cystectomy and myomectomy. For the training of young gynecologists, CLS should be emphasized in the early stage, and LESS should be introduced gradually.

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.

Eye-head coordination and dynamic visual scanning as indicators of visuo-cognitive demands in driving simulator

Driving is an everyday task involving a complex interaction between visual and cognitive processes. As such, an increase in the cognitive and/or visual demands can lead to a mental overload which can be detrimental for driving safety. Compiling evidence suggest that eye and head movements are relevant indicators of visuo-cognitive demands and attention allocation. This study aims to investigate the effects of visual degradation on eye-head coordination as well as visual scanning behavior during a highly demanding task in a driving simulator. A total of 21 emmetropic participants (21 to 34 years old) performed dual-task driving in which they were asked to maintain a constant speed on a highway while completing a visual search and detection task on a navigation device. Participants did the experiment with optimal vision and with contact lenses that introduced a visual perturbation (myopic defocus). The results indicate modifications of eye-head coordination and the dynamics of visual scanning in response to the visual perturbation induced. More specifically, the head was more involved in horizontal gaze shifts when the visual needs were not met. Furthermore, the evaluation of visual scanning dynamics, based on time-based entropy which measures the complexity and randomness of scanpaths, revealed that eye and gaze movements became less explorative and more stereotyped when vision was not optimal. These results provide evidence for a reorganization of both eye and head movements in response to increasing visual-cognitive demands during a driving task. Altogether, these findings suggest that eye and head movements can provide relevant information about visuo-cognitive demands associated with complex tasks. Ultimately, eye-head coordination and visual scanning dynamics may be good candidates to estimate drivers' workload and better characterize risky driving behavior.

Eye-Tracking Metrics Predict Perceived Workload in Robotic Surgical Skills Training

OBJECTIVE

The aim of this study is to assess the relationship between eye-tracking measures and perceived workload in robotic surgical tasks.

BACKGROUND

Robotic techniques provide improved dexterity, stereoscopic vision, and ergonomic control system over laparoscopic surgery, but the complexity of the interfaces and operations may pose new challenges to surgeons and compromise patient safety. Limited studies have objectively quantified workload and its impact on performance in robotic surgery. Although not yet implemented in robotic surgery, minimally intrusive and continuous eye-tracking metrics have been shown to be sensitive to changes in workload in other domains.

METHODS

Eight surgical trainees participated in 15 robotic skills simulation sessions. In each session, participants performed up to 12 simulated exercises. Correlation and mixed-effects analyses were conducted to explore the relationships between eye-tracking metrics and perceived workload. Machine learning classifiers were used to determine the sensitivity of differentiating between low and high workload with eye-tracking features.

RESULTS

Gaze entropy increased as perceived workload increased, with a correlation of .51. Pupil diameter and gaze entropy distinguished differences in workload between task difficulty levels, and both metrics increased as task level difficulty increased. The classification model using eye-tracking features achieved an accuracy of 84.7% in predicting workload levels.

CONCLUSION

Eye-tracking measures can detect perceived workload during robotic tasks. They can potentially be used to identify task contributors to high workload and provide measures for robotic surgery training.

APPLICATION

Workload assessment can be used for real-time monitoring of workload in robotic surgical training and provide assessments for performance and learning.

Associations between accommodative dynamics, heart rate variability and behavioural performance during sustained attention: A test-retest study

This study evaluated the time-on-task effect of a sustained attention task on the accommodative response, explored the link between ocular accommodation, cardiac autonomic regulation and behavioral performance, and tested the inter-session repeatability of these results by performing the same experimental procedure on different days. The accommodative response was measured in 25 university students using a WAM-5500 autorefractor, while participants performed a 10-minute psychomotor vigilance task at 50 cm. There were no time-on-task effects for the lag of accommodation, whereas the microfluctuations of accommodation and reaction time were modulated as a function of time-on-task, observing a progressive increment of both variables over time. Multiple regression analysis revealed that the microfluctuations of accommodation were a reasonably good predictor of behavioral performance. Analysis of inter-session repeatability showed that ocular accommodation, heart rate variability and reaction time had a low to moderate level of repeatability between two measurements. The microfluctuations of accommodation were sensitive to time-on-task effects during sustained attention, with a lower stability of accommodation being linked to reduced behavioral performance. The predictive capacity of the variability of accommodation for behavioral performance might be explained by the brain mechanisms shared by the ocular dynamics and attentional state; however, future studies would be required to elucidate this association. The low to moderate inter-session repeatability indicated that results in two measurement periods cannot be considered interchangeable, and therefore, the results of this study should be interpreted cautiously in this regard.

Detecting Mental Workload in Surgical Teams Using a Wearable Single-Channel Electroencephalographic Device

OBJECTIVE

To assess the sensitivity of an electroencephalographic (EEG)-based index, the prefrontal beta power, to quantify the mental workload in surgeons in real scenarios. Such EEG-based index might offer unique and unbiased measures of overload, a crucial factor when designing learning and training surgical programs.

DESIGN

The experiment followed a 2 × 2 × 2 within subjects design with 3 factors: (1) Surgical Role during the surgery (primary surgeon vs. assistant surgeon), (2) the Surgical Procedure (laparo-endoscopic single-site [LESS] surgery vs. multiport laparoscopic surgery [MPS]), and (3) the Suturing Techniques (interrupted vs. continuous suture).

SETTING

The study was carried out at the Advanced Multi-Purpose Simulation and Technological Innovation Complex situated at IAVANTE (Granada, Spain).

METHODS

Four surgical teams (primary surgeon and assistant surgeon, experts in MPS) performed 8 surgical exercises on porcine models, under different task complexities. They performed 2 suturing techniques (continuous and interrupted), employing a low complex procedure (MPS) and a high complex procedure (LESS). Surgeons acted as the primary surgeon during half of the exercises, and, as the assistant surgeon, during the rest of them. Simultaneously, we monitored EEG prefrontal EEG beta power spectra of both surgeons, using 2 synchronized wearable EEG devices. We also collected performance and subjective data.

RESULTS

Surgical complexity modulated prefrontal beta power. LESS surgery caused significant higher prefrontal beta power for both suturing techniques for both surgical roles which indicates higher demands than MPS. Perceived task complexity, overall surgical evaluation, and laparoscopic execution time confirmed EEG-based results. Finally, subjective ratings of surgical complexity differentiated between surgical roles within the same exercise, even when prefrontal beta power did not.

CONCLUSIONS

To detect mental overload when surgeons are engaged with complex surgeries, real or simulated, is still guesswork. EEG-based indices have great potential as objective and nonintrusive measures to assess mental overload in surgeons. Furthermore, EEG-based indices might play a relevant role in monitoring surgeons and residents' cognitive state during their training.

The effects of flight complexity on gaze entropy: An experimental study with fighter pilots

We studied the effects of task load variations as a function of flight complexity on combat pilots' gaze behavior (i.e., entropy) while solving in-flight emergencies. The second company of the Spanish Army Attack Helicopter Battalion (n = 15) performed three sets of standardized flight exercises with different levels of complexity (low [recognition flights], medium and high [emergency flights]). Throughout the flight exercises we recorded pilots' gaze entropy, as well as pilots' performance (assessed by an expert flight instructor) and subjective ratings of task load (assessed by the NASA-Task Load Index). Furthermore, we used pilots' electroencephalographic (EEG) activity as a reference physiological index for task load variations. We found that pilots' gaze entropy decreased ∼2% (i.e., visual scanning became less erratic) while solving the emergency flight exercises, showing a significant decreasing trend with increasing complexity (p < .05). This is in consonance with the ∼12% increase in the frontal theta band of their EEG spectra during said exercises. Pilots' errors and subjective ratings of task load increased as flight complexity increased (p-values < .05). Gaze data suggest that pilots used nondeterministic visual patterns when the aircraft was in an error-free state (low complexity), and changed their scanning behavior, becoming more deterministic, once emergencies occurred (medium/high complexity). Overall, our findings indicate that gaze entropy can serve as a sensitive index of task load in aviation settings.

Cognitive load theory for training health professionals in the workplace: A BEME review of studies among diverse professions: BEME Guide No. 53

AIM

Cognitive load theory (CLT) is of increasing interest to health professions education researchers. CLT has intuitive applicability to workplace settings, yet how CLT should inform teaching, learning, and research in health professions workplaces is unclear.

METHOD

To map the existing literature, we performed a scoping review of studies involving cognitive load, mental effort and/or mental workload in professional workplace settings within and outside of the health professions. We included actual and simulated workplaces and workplace tasks.

RESULT

Searching eight databases, we identified 4571 citations, of which 116 met inclusion criteria. Studies were most often quantitative. Methods to measure cognitive load included psychometric, physiologic, and secondary task approaches. Few covariates of cognitive load or performance were studied. Overall cognitive load and intrinsic load were consistently negatively associated with the level of experience and performance. Studies consistently found distractions and other aspects of workplace environments as contributing to extraneous load. Studies outside the health professions documented similar findings to those within the health professions, supporting relevance of CLT to workplace learning.

CONCLUSION

The authors discuss implications for workplace teaching, curricular design, learning environment, and metacognition. To advance workplace learning, the authors suggest future CLT research should address higher-level questions and integrate other learning frameworks.

Intraocular pressure increases after complex simulated surgical procedures in residents: an experimental study

BACKGROUND

Surgeons' overload is one of the main causes of medical errors that might compromise patient safety. Due to the drawbacks of current options to monitor surgeons' load, new, sensitive, and objective indices of task (over)load need to be considered and tested. In non-health-care scenarios, intraocular pressure (IOP) has been proved to be an unbiased physiological index, sensitive to task complexity (one of the main variables related to overload), and time on task. In the present study, we assessed the effects of demanding and complex simulated surgical procedures on surgical and medical residents' IOP.

METHODS

Thirty-four surgical and medical residents and healthcare professionals took part in this study (the experimental group, N = 17, and the control group, N = 17, were matched for sex and age). The experimental group performed two simulated bronchoscopy procedures that differ in their levels of complexity. The control group mimicked the same hand-eye movements and posture of the experimental group to help control for the potential effects of time on task and re-measurement on IOP. We measured IOP before and after each procedure, surgical performance during procedures, and perceived task complexity.

RESULTS

IOP increased as consequence of performing the most complex procedure only in the experimental group. Consistently, residents performed worse and reported higher perceived task complexity for the more complex procedure.

CONCLUSIONS

Our data show, for the first time, that IOP is sensitive to residents' task load, and it could be used as a new index to easily and rapidly assess task (over)load in healthcare scenarios. An arousal-based explanation is given to describe IOP variations due to task complexity.

Quantitative Evaluations of the Effects of Noise on Mental Workloads Based on Pupil Dilation during Laparoscopic Surgery

Noise can exert undeniable pressure on human minds, especially during tasks that require high precision and attention, such as those performed during surgery. To investigate whether auditory stimuli increases mental loads during laparoscopic surgery, we examined the effects of operating room (OR) noises and music by measuring mean changes in pupil sizes and subjectively assessing performances during surgery. We recruited 24 subjects with varying laparoscopic surgery experience levels to perform complete appendectomy using a laparoscopic simulator. Wearable eye trackers were worn by all subjects to monitor pupil sizes during surgery, and surgical tasks were performed under conditions of silence, background OR noise, and music. National Aeronautics and Space Administration-Task Load Index scores and performance parameters were also recorded during surgical tasks. Noise distractions were associated with significant increases in pupil sizes compared with those observed in silence, and the related increases in mental loads may have affected surgical performance. However, more experienced operators had smaller changes in pupil sizes because of auditory disturbances than moderately experienced surgeons. Noise stimulation in the OR increases surgeon's mental workload and performance. Auditory regulation of the OR may be better standardized using data from studies of the effects of acoustic stimulation in the OR, and mental stresses during surgery could be considered in a more humane manner. Further investigations are necessary to determine the cognitive consequences of various auditory stimuli.

Effect of examination stress on intraocular pressure in university students

Intraocular pressure (IOP) has been investigated as a possible objective index of mental stressors. Here, we assessed the effect of examination stress on IOP in 33 university students. A repeated-measures design was used with two experimental conditions (examination and control) and two points of measurements (pre- and post-sessions). Also, the cardiovascular response, subjective perceived stress, as well as calculated ocular perfusion pressure and blood-pulse pressure were determined. A Bayesian statistical analysis showed higher IOP values in the examination in comparison to the control condition (BF₀₁ < 0.001). A similar pattern was found for the cardiovascular indices (diastolic and systolic blood pressure, and heart rate), and these findings were corroborated by subjective reports (BF₀₁ < 0.001 in all cases). Our data incorporates evidence in relation to the utility of IOP as an objective marker of examination stress, and it may help in the assessment and management of stress in applied scenarios.