Detection of Changes in Surgical Difficulty

Estimating Cognitive Workload Using Task-Related Pupillary Responses in Simulated Drilling in Cochlear Implantation

OBJECTIVES

Training of temporal bone drilling requires more than mastering technical skills with the drill. Skills such as visual imagery, bimanual dexterity, and stress management need to be mastered along with precise knowledge of anatomy. In otorhinolaryngology, these psychomotor skills underlie performance in the drilling of the temporal bone for access to the inner ear in cochlear implant surgery. However, little is known about how psychomotor skills and workload management impact the practitioners' continuous and overall performance.

METHODS

To understand how the practitioner's workload and performance unfolds over time, we examine task-evoked pupillary responses (TEPR) of 22 medical students who performed transmastoid-posterior tympanotomy (TMPT) and removal of the bony overhang of the round window niche in a 3D-printed model of the temporal bone. We investigate how students' TEPR metrics (Average Pupil Size [APS], Index of Pupil Activity [IPA], and Low/High Index of Pupillary Activity [LHIPA]) and time spent in drilling phases correspond to the performance in key drilling phases.

RESULTS

All TEPR measures revealed significant differences between key drilling phases that corresponded to the anticipated workload. Enlarging the facial recess lasted significantly longer than other phases. IPA captured significant increase of workload in thinning of the posterior canal wall, while APS revealed increased workload during the drilling of the bony overhang.

CONCLUSION

Our findings contribute to the contemporary competency-based medical residency programs where objective and continuous monitoring of participants' progress allows to track progress in expertise acquisition. Laryngoscope, 2024.

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.

Using Task-Evoked Pupillary Response to Predict Clinical Performance during a Simulation Training

Training in healthcare skills can be affected by trainees' workload when completing a task. Due to cognitive processing demands being negatively correlated to clinical performance, assessing mental workload through objective measures is crucial. This study aimed to investigate task-evoked changes in pupil size as reliable markers of mental workload and clinical performance. A sample of 49 nursing students participated in a cardiac arrest simulation-based practice. Measurements of cognitive demands (NASA-Task Load Index), physiological parameters (blood pressure, oxygen saturation, and heart rate), and pupil responses (minimum, maximum, and difference diameters) throughout revealed statistically significant differences according to performance scores. The analysis of a multiple regression model produced a statistically significant pattern between pupil diameter differences and heart rate, systolic blood pressure, workload, and performance (R² = 0.280; F (6, 41) = 2.660; p < 0.028; d = 2.042). Findings suggest that pupil variations are promising markers to complement physiological metrics for predicting mental workload and clinical performance in medical practice.

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.

Artificial Intelligence for the Analysis of Workload-Related Changes in Radiologists' Gaze Patterns

Around 60-80% of radiological errors are attributed to overlooked abnormalities, the rate of which increases at the end of work shifts. In this study, we run an experiment to investigate if artificial intelligence (AI) can assist in detecting radiologists' gaze patterns that correlate with fatigue. A retrospective database of lung X-ray images with the reference diagnoses was used. The X-ray images were acquired from 400 subjects with a mean age of 49 ± 17, and 61% men. Four practicing radiologists read these images while their eye movements were recorded. The radiologists passed a series of concentration tests at prearranged breaks of the experiment. A U-Net neural network was adapted to annotate lung anatomy on X-rays and calculate coverage and information gain features from the radiologists' eye movements over lung fields. The lung coverage, information gain, and eye tracker-based features were compared with the cumulative work done (CDW) label for each radiologist. The gaze-traveled distance, X-ray coverage, and lung coverage statistically significantly (p < 0.01) deteriorated with cumulative work done (CWD) for three out of four radiologists. The reading time and information gain over lungs statistically significantly deteriorated for all four radiologists. We discovered a novel AI-based metric blending reading time, speed, and organ coverage, which can be used to predict changes in the fatigue-related image reading patterns.

When medical trainees encountering a performance difficulty: evidence from pupillary responses

BACKGROUND

Medical trainees are required to learn many procedures following instructions to improve their skills. This study aims to investigate the pupillary response of trainees when they encounter moment of performance difficulty (MPD) during skill learning. Detecting the moment of performance difficulty is essential for educators to assist trainees when they need it.

METHODS

Eye motions were recorded while trainees practiced the thoracostomy procedure in the simulation model. To make pupillary data comparable among trainees, we proposed the adjusted pupil size (APS) normalizing pupil dilation for each trainee in their entire procedure. APS variables including APS, maxAPS, minAPS, meanAPS, medianAPS, and max interval indices were compared between easy and difficult subtasks; the APSs were compared among the three different performance situations, the moment of normal performance (MNP), MPD, and moment of seeking help (MSH).

RESULTS

The mixed ANOVA revealed that the adjusted pupil size variables, such as the maxAPS, the minAPS, the meanAPS, and the medianAPS, had significant differences between performance situations. Compared to MPD and MNP, pupil size was reduced during MSH. Trainees displayed a smaller accumulative frequency of APS during difficult subtask when compared to easy subtasks.

CONCLUSIONS

Results from this project suggest that pupil responses can be a good behavioral indicator. This study is a part of our research aiming to create an artificial intelligent system for medical trainees with automatic detection of their performance difficulty and delivering instructional messages using augmented reality technology.

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.

Spatial Sound in a 3D Virtual Environment: All Bark and No Bite?

Although the focus of Virtual Reality (VR) lies predominantly on the visual world, acoustic components enhance the functionality of a 3D environment. To study the interaction between visual and auditory modalities in a 3D environment, we investigated the effect of auditory cues on visual searches in 3D virtual environments with both visual and auditory noise. In an experiment, we asked participants to detect visual targets in a 360° video in conditions with and without environmental noise. Auditory cues indicating the target location were either absent or one of simple stereo or binaural audio, both of which assisted sound localization. To investigate the efficacy of these cues in distracting environments, we measured participant performance using a VR headset with an eye tracker. We found that the binaural cue outperformed both stereo and no auditory cues in terms of target detection irrespective of the environmental noise. We used two eye movement measures and two physiological measures to evaluate task dynamics and mental effort. We found that the absence of a cue increased target search duration and target search path, measured as time to fixation and gaze trajectory lengths, respectively. Our physiological measures of blink rate and pupil size showed no difference between the different stadium and cue conditions. Overall, our study provides evidence for the utility of binaural audio in a realistic, noisy and virtual environment for performing a target detection task, which is a crucial part of everyday behaviour—finding someone in a crowd.

Detecting Task Difficulty of Learners in Colonoscopy: Evidence from Eye-Tracking

Eye-tracking can help decode the intricate control mechanism in human performance. In healthcare, physicians-in-training require extensive practice to improve their healthcare skills. When a trainee encounters any difficulty in the practice, they will need feedback from experts to improve their performance. Personal feedback is time-consuming and subjected to bias. In this study, we tracked the eye movements of trainees during their colonoscopic performance in simulation. We examined changes in eye movement behavior during the moments of navigation loss (MNL), a signature sign for task difficulty during colonoscopy, and tested whether deep learning algorithms can detect the MNL by feeding data from eye-tracking. Human eye gaze and pupil characteristics were learned and verified by the deep convolutional generative adversarial networks (DCGANs); the generated data were fed to the Long Short-Term Memory (LSTM) networks with three different data feeding strategies to classify MNLs from the entire colonoscopic procedure. Outputs from deep learning were compared to the expert's judgment on the MNLs based on colonoscopic videos. The best classification outcome was achieved when we fed human eye data with 1000 synthesized eye data, where accuracy (91.80%), sensitivity (90.91%), and specificity (94.12%) were optimized. This study built an important foundation for our work of developing an education system for training healthcare skills using simulation.

Action-related eye measures to assess surgical expertise

Background

Eye-tracking offers a new list of performance measures for surgeons. Previous studies of eye-tracking have reported that action-related fixation is a good measuring tool for elite task performers. Other measures, including early eye engagement to target and early eye disengagement from the previous subtask, were also reported to distinguish between different expertise levels. These parameters were examined during laparoscopic surgery simulations in the present study, with a goal to identify the most useful measures for distinguishing surgical expertise.

Methods

Surgical operators, including experienced surgeons (expert), residents (intermediate), and university students (novice), were required to perform a laparoscopic task involving reaching, grasping, and loading, while their eye movements and performance videos were recorded. Spatiotemporal features of eye–hand coordination and action-related fixation were calculated and compared among the groups.

Results

The study included five experienced surgeons, seven residents, and 14 novices. Overall, experts performed tasks faster than novices. Examining eye–hand coordination on each subtask, it was found that experts managed to disengage their eyes earlier from the previous subtask, whereas novices disengaged their eyes from previous subtask with a significant delay. Early eye engagement to the current subtask was observed for all operators. There was no difference in action-related fixation between experienced surgeons and novices. Disengage time was strongly associated with the surgical experience score of the operators, better than both early-engage time and action-related fixation.

Conclusion

The spatiotemporal features of surgeons’ eye–hand coordination can be used to assess level of surgical experience.

Machine learning-based analysis of operator pupillary response to assess cognitive workload in clinical ultrasound imaging

Introduction

Pupillometry, the measurement of eye pupil diameter, is a well-established and objective modality correlated with cognitive workload. In this paper, we analyse the pupillary response of ultrasound imaging operators to assess their cognitive workload, captured while they undertake routine fetal ultrasound examinations. Our experiments and analysis are performed on real-world datasets obtained using remote eye-tracking under natural clinical environmental conditions.

Methods

Our analysis pipeline involves careful temporal sequence (time-series) extraction by retrospectively matching the pupil diameter data with tasks captured in the corresponding ultrasound scan video in a multi-modal data acquisition setup. This is followed by the pupil diameter pre-processing and the calculation of pupillary response sequences. Exploratory statistical analysis of the operator pupillary responses and comparisons of the distributions between ultrasonographic tasks (fetal heart versus fetal brain) and operator expertise (newly-qualified versus experienced operators) are performed. Machine learning is explored to automatically classify the temporal sequences into the corresponding ultrasonographic tasks and operator experience using temporal, spectral, and time-frequency features with classical (shallow) models, and convolutional neural networks as deep learning models.

Results

Preliminary statistical analysis of the extracted pupillary response shows a significant variation for different ultrasonographic tasks and operator expertise, suggesting different extents of cognitive workload in each case, as measured by pupillometry. The best-performing machine learning models achieve receiver operating characteristic (ROC) area under curve (AUC) values of 0.98 and 0.80, for ultrasonographic task classification and operator experience classification, respectively.

Conclusion

We conclude that we can successfully assess cognitive workload from pupil diameter changes measured while ultrasound operators perform routine scans. The machine learning allows the discrimination of the undertaken ultrasonographic tasks and scanning expertise using the pupillary response sequences as an index of the operators’ cognitive workload. A high cognitive workload can reduce operator efficiency and constrain their decision-making, hence, the ability to objectively assess cognitive workload is a first step towards understanding these effects on operator performance in biomedical applications such as medical imaging.

•

Machine learning-based pupillary response analysis is performed to assess operator cognitive workload in clinical ultrasound.

•

A systematic multi-modal data analysis pipeline is proposed using eye-tracking, pupillometry, and sonography data science.

•

Pertinent challenges of natural or real-world clinical datasets are addressed.

•

Pupillary responses around event triggers, different ultrasonographic tasks, and different operator experiences are studied.

•

Machine learning models are learnt to classify undertaken tasks or operator expertise from pupillometric time-series data.

The Application of a System of Eye Tracking in Laparoscopic Surgery: A New Didactic Tool to Visual Instructions

Introduction: Laparoscopic surgery is an increasingly used technique, but it requires a high degree of learning, and communication between the operating room crew is considerably difficult. The use of eye tracking has been proposed as a didactic and evaluation tool in several settings, including in laparoscopy in simulators.

Objectives: This study aimed to evaluate the usefulness of the use of eye tracking systems (Tobii glasses 2) in laparoscopic surgery as a didactic and assessment tool to improve communication in the operating room and improve patients' security.

Methodology: An anonymous survey was sent to the students and medical teachers of a faculty of medicine and practicing doctors and residents. The message contained an explanation about the use of the Tobii glasses, a link to watch the video showing its use in a laparoscopic surgery, and the survey to complete after watching the video.

Results: The survey was answered by 113 participants (51.3% medical students, 27.4% medical teachers, 18.6% practicing doctors, and 2.7% medicine residents). Eighty-three percent agreed with the usefulness of the “Tobii glasses” in the operating room for improving communication between the main surgeon and the assistant, for learning complex surgery techniques, for obtaining didactic videos, and for indicating anatomical structures. The item scored worst was the price of the glasses.

Conclusions: It is possible to record and project expert gaze patterns in the operating room in real time using the Tobii glasses. This device allows improving communication among the surgical crew and the learning of residents and also improving the security of surgical patients.

Using Eye Tracking for Measuring Cognitive Workload During Clinical Simulations: Literature Review and Synthesis

High-fidelity clinical simulations can be used by clinicians to acquire technical (physical ability and knowledge) and non-technical (cognitive and social processes) skills. Excessive cognitive workload contributes to medical errors because of the impact on both technical and non-technical skills. Many studies measure cognitive workload with psychometric instruments that limit the assessment of cognitive workload to a single time period and may involve response bias. Using eye tracking to measure task-evoked pupillary responses allows the measurement of changes in pupil diameter related to the cognitive workload associated with a specific activity. Incorporating eye tracking with high-fidelity clinical simulations provides a reliable and continuous assessment of cognitive workload. The purpose of this literature review is to summarize the use of eye-tracking technology to measure cognitive workload of healthcare providers to generate evidence-based guidelines for measuring cognitive workload during high-fidelity clinical simulations. What this manuscript adds to the body of literature is a summary of best practices related to the different methods of measuring cognitive workload, benefits and limitations of using eye tracking, and high-fidelity clinical simulation design considerations for successful integration of eye tracking.

Predictors of Nursing Clinical Judgment in Simulation

ABSTRACT

This was a pilot study of novice and expert nurses participating in a simulation to determine the predictors of clinical judgment. Covariates included age, nursing experience, simulation experience, and six measures of pupil dilation as a measure of stress with scores on the Lasater Clinical Judgment Rubric as the dependent variable. A stepwise linear regression found years of RN experience was the only predictor of better clinical judgment. Despite evidence of stress, only years as a nurse was a statistically significant predictor.

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-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.

Distinguishing Intermediate and Novice Surgeons by Eye Movements

Surgical skill-level assessment is key to collecting the required feedback and adapting the educational programs accordingly. Currently, these assessments for the minimal invasive surgery programs are primarily based on subjective methods, and there is no consensus on skill level classifications. One of the most detailed of these classifications categorize skill levels as beginner, novice, intermediate, sub-expert, and expert. To properly integrate skill assessment into minimal invasive surgical education programs and provide skill-based training alternatives, it is necessary to classify the skill levels in as detailed a way as possible and identify the differences between all skill levels in an objective manner. Yet, despite the existence of very encouraging results in the literature, most of the studies have been conducted to better understand the differences between novice and expert surgical skill levels leaving out the other crucial skill levels between them. Additionally, there are very limited studies by considering the eye-movement behaviors of surgical residents. To this end, the present study attempted to distinguish novice- and intermediate-level surgical residents based on their eye movements. The eye-movement data was recorded from 23 volunteer surgical residents while they were performing four computer-based simulated surgical tasks under different hand conditions. The data was analyzed using logistic regression to estimate the skill levels of both groups. The best results of the estimation revealing a 91.3% recognition rate of predicting novice and intermediate surgical residents on one scenario were selected from four under the dominant hand condition. These results show that the eye-movements can be potentially used to identify surgeons with intermediate and novice skills. However, the results also indicate that the order in which the scenarios are provided, and the design of the scenario, the tasks, and their appropriateness with the skill levels of the participants are all critical factors to be considered in improving the estimation ratio, and hence require thorough assessment for future research.

Integrating Eye-Tracking to Augmented Reality System for Surgical Training

Augmented Reality has been utilized for surgical training. During the implementation, displaying instructional information at the right moment is critical for skill acquisition. We built a new surgical training platform combining augmented reality system (HoloLens, Microsoft) with an eye-tracker (Pupil labs, Germany). Our goal is to detect the moments of performance difficulty using the integrated eye-tracker so that the system could display instructions at the precise moment when the user is seeking instructional information during a surgical skill practice in simulation. In the paper, we describe the system design, system calibration and data transferring between these devices.

Simulation-based training of critical events during cardiopulmonary bypass: importance of a critical events checklist

Objectives:

Evaluation of critical events training for clinical perfusionists is necessary to improve this educational approach. Critical events checklists are effective in reducing clinical complications, but should be tested in a simulation environment first. Individual behavior and stress response of clinical perfusionists during simulated critical events on cardiopulmonary bypass have not been evaluated yet. This study focuses on the evaluation of critical events training and critical events checklists in simulated cardiopulmonary bypass.

Methods:

A total of 19 clinical perfusionists from a single hospital took part in two simulated critical event scenarios. Clinical perfusionist behavior and physiological responses were recorded using eye tracking, heart rate variability, video, and audio. In addition, workloads were determined and participants were interviewed.

Results:

Relevant areas of interest were identified for each simulation phase. During critical event detection and subsequent decision-making, areas of interest hits and fixation durations varied with the use of a critical events checklist. Times to decision were shorter, decision quality was higher, and temporal workload was increased when the checklist was used. Evaluation of selected heart rate variability measures revealed a good correlation with pupil diameters.

Conclusion:

Evaluation of critical events during simulated cardiopulmonary bypass shows that the scenario is realistic and relevant for clinical practice. Integrating a critical events checklist improves the probability of correct decision-making and shortens the correct decision time. Temporal workload is increased when using a checklist. Eye tracking and heart rate variability are well suited to evaluate participants’ behaviors and stress levels. All participants welcomed simulation training for critical incidents.

Combined Gaze Metrics as Stress-Sensitive Indicators of Microsurgical Proficiency

Background. Evaluation of microsurgical proficiency is conventionally subjective, time consuming, and unreliable. Eye movement–based metrics have been promising not only in detection of surgical expertise but also in identifying actual cognitive stress and workload. We investigated if pupil dilations and blinks could be utilized in parallel to accurately classify microsurgical proficiency and its moderating features, especially task-related stress. Methods. Participants (n = 11) were divided into groups based on prior experience in microsurgery: novices (n = 6) with no experience and trained microsurgeons (n = 5). All participants conducted standardized suturing tasks with authentic instruments and a surgical microscope. A support vector machine classifier was used to classify features of microsurgical expertise based on percentage changes in pupil size. Results. A total of 109 successful sutures with 1090 segments were recorded. Classification of expertise from sutures achieved accuracies between 74.3% and 76.0%. Classification from individual segments based on these same features was not feasible. Conclusions. Combined gaze metrics are applicable for classifying surgical proficiency during a defined task. Pupil dilation is also sensitive to external stress factors; however, the usefulness of blinks is impaired by low blink rates. The results can be translated to surgical education to improve feedback and should be investigated individually in the context of actual performance and in real patient operations. Combined gaze metrics may be ultimately utilized to help microsurgeons monitor their performance and workload in real time—which may lead to prevention of errors.

Pupil diameter differentiates expertise in dental radiography visual search

Expert behavior is characterized by rapid information processing abilities, dependent on more structured schemata in long-term memory designated for their domain-specific tasks. From this understanding, expertise can effectively reduce cognitive load on a domain-specific task. However, certain tasks could still evoke different gradations of load even for an expert, e.g., when having to detect subtle anomalies in dental radiographs. Our aim was to measure pupil diameter response to anomalies of varying levels of difficulty in expert and student dentists’ visual examination of panoramic radiographs. We found that students’ pupil diameter dilated significantly from baseline compared to experts, but anomaly difficulty had no effect on pupillary response. In contrast, experts’ pupil diameter responded to varying levels of anomaly difficulty, where more difficult anomalies evoked greater pupil dilation from baseline. Experts thus showed proportional pupillary response indicative of increasing cognitive load with increasingly difficult anomalies, whereas students showed pupillary response indicative of higher cognitive load for all anomalies when compared to experts.

Visual behaviour in robotic surgery-Demonstrating the validity of the simulated environment

BACKGROUND

Eye metrics provide insight into surgical behaviour allowing differentiation of performance, however have not been used in robotic surgery. This study explores eye metrics of robotic surgeons in training in simulated and real tissue environments.

METHODS

Following the Fundamentals of Robotic Surgery (FRS), training curriculum novice robotic surgeons were trained to expert-derived benchmark proficiency using real tissue on the da Vinci Si and the da Vinci skills simulator (dVSS) simulator. Surgeons eye metrics were recorded using eye-tracking glasses when both "novice" and "proficient" in both environments. Performance was assessed using Global Evaluative Assessment of Robotic skills (GEARS) and numeric psychomotor test score (NPMTS) scores.

RESULTS

Significant (P ≤ .05) correlations were seen between pupil size, rate of change and entropy, and associated GEARS/NPMTS in "novice" and "proficient" surgeons. Only number of blinks per minute was significantly different between pupilometrics in the simulated and real tissue environments.

CONCLUSIONS

This study illustrates the value of eye tracking as an objective physiological tool in the robotic setting. Pupilometrics significantly correlate with established assessment methods and could be incorporated into robotic surgery assessments.

Are Left- and Right-Eye Pupil Sizes Always Equal?

Eye movements provide very critical information about the cognitive load and behaviors of human beings. Earlier studies report that under normal conditions, the left- and right-eye pupil sizes are equal. For this reason, most studies undertaking eye-movement analysis are conducted by only considering the pupil size of a single eye or taking the average size of both eye pupils. This study attempts to offer a better understanding concerning whether there are any differences between the left- and right-eye pupil sizes of the right-handed surgical residents while performing surgical tasks in a computer-based simulation environment under different conditions (left-hand, right-hand and both hands). According to the results, in many cases, the right-eye pupil sizes of the participants were larger than their left-eye pupil sizes while performing the tasks under right-hand and both hands conditions. However, no significant difference was found in relation to the tasks performed under left-hand condition in all scenarios. These results are very critical to shed further light on the cognitive load of the surgical residents by analyzing their left-eye and right-eye pupil sizes. Further research is required to investigate the effect of the difficulty level of each scenario, its appropriateness with the skill level of the participants, and handedness on the differences between the leftand right-eye pupil sizes.

Evaluation of attention, perception, and stress levels of clinical cardiovascular perfusionists during cardiac operations: a pilot study

BACKGROUND

Performing cardiopulmonary bypass is a complex task which involves evaluating visual input from patient monitors and technical parameters displayed at the heart-lung machine console as well as reacting to other sensory input. Only few studies are available concerning the competency requirements for clinical cardiovascular perfusionists, including attention, perception, and coping with mental stress. This study aims at evaluating attention, perception, and stress levels of clinical cardiovascular perfusionists during cardiopulmonary bypass.

METHODS

Nine clinical cardiovascular perfusionists voluntarily offered to participate in the study. Participants were asked to wear Tobii 2 eye-tracking glasses throughout the procedures. Specific time points were analyzed (cardiopulmonary bypass on, initial cardioplegia delivery, steady state, cross-clamp off, and weaning from cardiopulmonary bypass). Data acquisition was supplemented by participants' self-evaluation regarding their stress levels and by National Aeronautics and Space Administration Task Load Index (NASA TLX) questionnaires.

RESULTS

Seven datasets were sufficient to be evaluated. The clinical cardiovascular perfusionists' professional experience ranged from 0.5 to 24 years. Evaluation of eye-tracking data revealed large variations in areas of interest hits, fixation, and dwell times. Across all phases, the venous reservoir, mean arterial pressure, arterial pump display, cardioplegia control, and data management system received the highest levels of attention. Pupil diameter measurements increased at start of cardiopulmonary bypass, cardioplegia delivery, and weaning off, but returned to base level during steady state. Clinical cardiovascular perfusionists' self-evaluation showed that subjective stress level was highest at the start and the end of the procedure. NASA TLX questionnaires revealed medium-to-high mental and temporal workloads, but low physical workloads. Performance, effort, and frustration indices showed medium workloads.

CONCLUSION

During cardiopulmonary bypass, perfusionists are subjected to stress. Peak stress levels were highest during start and end of cardiopulmonary bypass. Furthermore, visual attention and perception varied between the operative phases. Further studies are indicated to evaluate the design of heart-lung machines and stress-coping strategies during cardiopulmonary bypass.

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.

Insights From Pupil Size to Mental Workload of Surgical Residents: Feasibility of an Educational Computer-Based Surgical Simulation Environment (ECE) Considering the Hand Condition

The advantage of simulation environments is that they present various insights into real situations, where experimental research opportunities are very limited—for example, in endoscopic surgery. These operations require simultaneous use of both hands. For this reason, surgical residents need to develop several motor skills, such as eye-hand coordination and left-right hand coordination. While performing these tasks, the hand condition (dominant, nondominant, both hands) creates different degrees of mental workload, which can be assessed through mental physiological measures—namely, pupil size. Studies show that pupil size grows in direct proportion to mental workload. However, in the literature, there are very limited studies exploring this workload through the pupil sizes of the surgical residents under different hand conditions. Therefore, in this study, we present a computer-based simulation of a surgical task using eye-tracking technology to better understand the influence of the hand condition on the performance of skill-based surgical tasks in a computer-based simulated environment. The results show that under the both-hand condition, the pupil size of the surgical residents is larger than the one under the dominant and nondominant hand conditions. This indicates that when the computer-simulated surgical task is performed with both hands, it is considered more difficult than in the dominant and nondominant hand conditions. In conclusion, this study shows that pupil size measurements are sufficiently feasible to estimate the mental workload of the participants while performing surgical tasks. The results of this study can be used as a guide by instructional system designers of skill-based training programs.

Ergonomic Assessment of the Mental Workload Confronted by Surgeons during Laparoscopic Surgery

Although the mental workload confronted by laparoscopic surgeons is rather high, there is presently no reliable, established method for evaluating this workload. In the present study, four evaluation indices of eye movement metrics were applied to evaluate surgeons’ mental workload. Correlations between these indices and National Aeronautics and Space Administration Task Load Index (NASA-TLX) scores were also explored. Sixteen participants were recruited to complete four laparoscopic procedures. Eye movement was recorded during the tasks, and NASA-TLX scales were also introduced for subjective evaluation. The data were analyzed using R 3.3.2. Significant differences in the mental workload of each task were observed. Statistically significant correlations between mean pupil diameter change and NASA-TLX scores were also observed. The correlation coefficients were 0.763, 0.675, 0.405, and 0.547, and the P values correspondingly were 0.001, 0.004, 0.12, and 0.028, respectively. The results clarify that the mental workload of laparoscopic surgeons is dependent on the specific demands of the operation. Appropriate objective physiological indices can be used to identify the mental workload state of the surgeon.

Using Eye-Movement Events to Determine the Mental Workload of Surgical Residents

These days, eye-tracking is one of the promising technologies used in different fields such as aviation, arts, sports, psychology and driving for several purposes. Even though it is being used for health purposes, studies involving eye-tracking are rare in the field of endo-neurosurgery. This study aims to use this technology to promote our understanding of the effect related to computer-based instructional materials on mental workload of endo-neurosurgery residents. Four computer-based simulation scenarios are developed based on skill development requirements of endo-neurosurgery residents. Two of them were designed as general models and the other two as simulated surgical models. During these surgery procedures, in real settings, surgical residents need to use their both hands simultaneously to control the endoscope and the operational tool in a coordinated fashion. Therefore, to shed light on the participants' behaviors, these scenarios are performed with dominant-hand, non-dominant hand and, finally with both-hands using haptic interfaces. Twenty-three residents volunteered in this study. Their eye-movements were recorded while performing the scenarios. According to the results of this study, when performing the simulated surgical models, an increase in the participants' mental workload was recorded when compared to the other scenarios. Accordingly, it can be concluded that the eye-movements of surgical residents can provide insights about the anticipated level of difficulty about the skill-based tasks. This information might be very critical to properly design and organize instructional materials for endo-neurosurgery, and also to better guide and evaluate the progress of trainees in computer simulation-based skill training environments.

Use of Eye Tracking as an Innovative Instructional Method in Surgical Human Anatomy

OBJECTIVE

Tobii glasses can record corneal infrared light reflection to track pupil position and to map gaze focusing in the video recording. Eye tracking has been proposed for use in training and coaching as a visually guided control interface. The aim of our study was to test the potential use of these glasses in various situations: explanations of anatomical structures on tablet-type electronic devices, explanations of anatomical models and dissected cadavers, and during the prosection thereof. An additional aim of the study was to test the use of the glasses during laparoscopies performed on Thiel-embalmed cadavers (that allows pneumoinsufflation and exact reproduction of the laparoscopic surgical technique). The device was also tried out in actual surgery (both laparoscopy and open surgery).

DESIGN

We performed a pilot study using the Tobii glasses.

SETTING

Dissection room at our School of Medicine and in the operating room at our Hospital.

PARTICIPANTS

To evaluate usefulness, a survey was designed for use among students, instructors, and practicing physicians.

RESULTS

The results were satisfactory, with the usefulness of this tool supported by more than 80% positive responses to most questions. There was no inconvenience for surgeons and that patient safety was ensured in the real laparoscopy.

CONCLUSION

To our knowledge, this is the first publication to demonstrate the usefulness of eye tracking in practical instruction of human anatomy, as well as in teaching clinical anatomy and surgical techniques in the dissection and operating rooms.

Pupil diameter changes reflect difficulty and diagnostic accuracy during medical image interpretation

Background

No automated methods exist to objectively monitor and evaluate the diagnostic process while physicians review computerized medical images. The present study tested whether using eye tracking to monitor tonic and phasic pupil dynamics may prove valuable in tracking interpretive difficulty and predicting diagnostic accuracy.

Methods

Pathologists interpreted digitized breast biopsies varying in diagnosis and rated difficulty, while pupil diameter was monitored. Tonic diameter was recorded during the entire duration of interpretation, and phasic diameter was examined when the eyes fixated on a pre-determined diagnostic region during inspection.

Results

Tonic pupil diameter was higher with increasing rated difficulty levels of cases. Phasic diameter was interactively influenced by case difficulty and the eventual agreement with consensus diagnosis. More difficult cases produced increases in pupil diameter, but only when the pathologists’ diagnoses were ultimately correct. All results were robust after adjusting for the potential impact of screen brightness on pupil diameter.

Conclusions

Results contribute new understandings of the diagnostic process, theoretical positions regarding locus coeruleus-norepinephrine system function, and suggest novel approaches to monitoring, evaluating, and guiding medical image interpretation.

Gaze entropy reflects surgical task load

BACKGROUND

Task (over-)load imposed on surgeons is a main contributing factor to surgical errors. Recent research has shown that gaze metrics represent a valid and objective index to asses operator task load in non-surgical scenarios. Thus, gaze metrics have the potential to improve workplace safety by providing accurate measurements of task load variations. However, the direct relationship between gaze metrics and surgical task load has not been investigated yet. We studied the effects of surgical task complexity on the gaze metrics of surgical trainees.

METHODS

We recorded the eye movements of 18 surgical residents, using a mobile eye tracker system, during the performance of three high-fidelity virtual simulations of laparoscopic exercises of increasing complexity level: Clip Applying exercise, Cutting Big exercise, and Translocation of Objects exercise. We also measured performance accuracy and subjective rating of complexity.

RESULTS

Gaze entropy and velocity linearly increased with increased task complexity: Visual exploration pattern became less stereotyped (i.e., more random) and faster during the more complex exercises. Residents performed better the Clip Applying exercise and the Cutting Big exercise than the Translocation of Objects exercise and their perceived task complexity differed accordingly.

CONCLUSIONS

Our data show that gaze metrics are a valid and reliable surgical task load index. These findings have potential impacts to improve patient safety by providing accurate measurements of surgeon task (over-)load and might provide future indices to assess residents' learning curves, independently of expensive virtual simulators or time-consuming expert evaluation.

The impact of expert visual guidance on trainee visual search strategy, visual attention and motor skills

Minimally invasive and robotic surgery changes the capacity for surgical mentors to guide their trainees with the control customary to open surgery. This neuroergonomic study aims to assess a "Collaborative Gaze Channel" (CGC); which detects trainer gaze-behavior and displays the point of regard to the trainee. A randomized crossover study was conducted in which twenty subjects performed a simulated robotic surgical task necessitating collaboration either with verbal (control condition) or visual guidance with CGC (study condition). Trainee occipito-parietal (O-P) cortical function was assessed with optical topography (OT) and gaze-behavior was evaluated using video-oculography. Performance during gaze-assistance was significantly superior [biopsy number: (mean ± SD): control = 5.6 ± 1.8 vs. CGC = 6.6 ± 2.0; p < 0.05] and was associated with significantly lower O-P cortical activity [ΔHbO2 mMol × cm [median (IQR)] control = 2.5 (12.0) vs. CGC 0.63 (11.2), p < 0.001]. A random effect model (REM) confirmed the association between guidance mode and O-P excitation. Network cost and global efficiency were not significantly influenced by guidance mode. A gaze channel enhances performance, modulates visual search, and alleviates the burden in brain centers subserving visual attention and does not induce changes in the trainee's O-P functional network observable with the current OT technique. The results imply that through visual guidance, attentional resources may be liberated, potentially improving the capability of trainees to attend to other safety critical events during the procedure.