Cognitive and motor skill competence are different: Results from a prospective randomized trial using virtual reality simulator and educational video in laparoscopic cholecystectomy.

BACKGROUND AND PURPOSE: Cognitive transfer represents an important issue in surgical education. It is essential for the acquisition of competence, such as decision making and error avoidance. This randomized study aims to compare the effectivity of cognitive transfer by observing the surgery versus using modern virtual reality simulators for learning a laparoscopic cholecystectomy. METHOD: This was a prospective, randomized, single centre study. 40 medical students from a university hospital, a tertiary care teaching institution, were enrolled. After a short introduction of laparoscopic cholecystectomy, they were randomized into two groups (video group and simulator group). In the video group, participants watched the step-by-step educational video twice. In the simulator group, participants underwent training using the virtual reality simulator, including tutorial procedural tasks of laparoscopic cholecystectomy as well as a complete cholecystectomy on the simulator. After the training, cognitive competence including decision making and error awareness was assessed using a questionnaire. RESULTS: In the most critical step of laparoscopic cholecystectomy, "Dissection in Calot's triangle", as well as in the aspect of planning next step, the video group was superior significantly (P = 0.038 and P = 0.04). No significant differences concerning the recognition of critical anatomical structures, choosing the necessary instruments as well as error awareness were found. CONCLUSIONS: Learning by watching a high-quality educational video is more effective in acquiring the cognitive competence to combine learned single tasks. Traditional learning means as watching educational videos and modern, sophisticated VRS should be deployed complementarily to establish cognitive and motor competencies separately.

Transferability of laparoscopic skills using the virtual reality simulator.

BACKGROUND: Skill transfer represents an important issue in surgical education, and is not well understood. The aim of this randomized study is to assess the transferability of surgical skills between two laparoscopic abdominal procedures using the virtual reality simulator in surgical novices. METHODS: From September 2016 to July 2017, 44 surgical novices were randomized into two groups and underwent a proficiency-based basic training consisting of five selected simulated laparoscopic tasks. In group 1, participants performed an appendectomy training on the virtual reality simulator until they reached a defined proficiency. They moved on to the tutorial procedural tasks of laparoscopic cholecystectomy. Participants in group 2 started with the tutorial procedural tasks of laparoscopic cholecystectomy directly. Finishing the training, participants of both groups were required to perform a complete cholecystectomy on the simulator. Time, safety and economy parameters were analysed. RESULTS: Significant differences in the demographic characteristics and previous computer games experience between the two groups were not noted. Both groups took similar time to complete the proficiency-based basic training. Participants in group 1 needed significantly less movements (388.6 ± 98.6 vs. 446.4 ± 81.6; P < 0.05) as well as shorter path length (810.2 ± 159.5 vs. 945.5 ± 187.8 cm; P < 0.05) to complete the cholecystectomy compared to group 2. Time and safety parameters did not differ significantly between both groups. CONCLUSION: The data demonstrate a positive transfer of motor skills between laparoscopic appendectomy and cholecystectomy on the virtual reality simulator; however, the transfer of cognitive skills is limited. Separate training curricula seem to be necessary for each procedure for trainees to practise task-specific cognitive skills effectively. Mentoring could help trainees to get a deeper understanding of the procedures, thereby increasing the chance for the transfer of acquired skills.

Ambient and focal attention during complex problem-solving: preliminary evidence from real-world eye movement data.

Time course analysis of eye movements during free exploration of real-world scenes often reveals an increase in fixation durations together with a decrease in saccade amplitudes, which has been explained within the two visual systems approach, i.e., a transition from ambient to focal. Short fixations and long saccades during early viewing periods are classified as ambient mode of vision, which is concerned with spatial orientation and is related to simple visual properties such as motion, contrast, and location. Longer fixations and shorter saccades during later viewing periods are classified as focal mode of vision, which is concentrated in the foveal projection and is capable of object identification and its semantic categorization. While these findings are mainly obtained in the context of image exploration, the present study endeavors to investigate whether the same pattern of interplay between ambient and focal visual attention is deployed when people work on complex real-world tasks-and if so, when? Based on a re-analysis of existing data that integrates concurrent think aloud and eye tracking protocols, the present study correlated participants' internal thinking models to the parameters of their eye movements when they planned solutions to an open-ended design problem in a real-world setting. We hypothesize that switching between ambient and focal attentional processing is useful when solvers encounter difficulty compelling them to shift their conceptual direction to adjust the solution path. Individuals may prefer different attentional strategies for information-seeking behavior, such as ambient-to-focal or focal-to-ambient. The observed increase in fixation durations and decrease in saccade amplitudes during the periods around shifts in conceptual direction lends support to the postulation of the ambient-to-focal processing; however, focal-to-ambient processing is not evident. Furthermore, our data demonstrate that the beginning of a shift in conceptual direction is observable in eye movement behavior with a significant prolongation of fixation. Our findings add to the conclusions drawn from laboratory settings by providing preliminary evidence for ambient and focal processing characteristics in real-world problem-solving.

Assessment of the human response to acute mental stress-An overview and a multimodal study.

Numerous vital signs are reported in association with stress response assessment, but their application varies widely. This work provides an overview over methods for stress induction and strain assessment, and presents a multimodal experimental study to identify the most important vital signs for effective assessment of the response to acute mental stress. We induced acute mental stress in 65 healthy participants with the Mannheim Multicomponent Stress Test and acquired self-assessment measures (Likert scale, Self-Assessment Manikin), salivary α-amylase and cortisol concentrations as well as 60 vital signs from biosignals, such as heart rate variability parameters, QT variability parameters, skin conductance level, and breath rate. By means of statistical testing and a self-optimizing logistic regression, we identified the most important biosignal vital signs. Fifteen biosignal vital signs related to ventricular repolarization variability, blood pressure, skin conductance, and respiration showed significant results. The logistic regression converged with QT variability index, left ventricular work index, earlobe pulse arrival time, skin conductance level, rise time and number of skin conductance responses, breath rate, and breath rate variability (F1 = 0.82). Self-assessment measures indicated successful stress induction. α-amylase and cortisol showed effect sizes of -0.78 and 0.55, respectively. In summary, the hypothalamic-pituitary-adrenocortical axis and sympathetic nervous system were successfully activated. Our findings facilitate a coherent and integrative understanding of the assessment of the stress response and help to align applications and future research concerning acute mental stress.

Eye movement patterns in complex tasks: Characteristics of ambient and focal processing.

Analyzing the time course of eye movements during scene viewing often indicates that people progress through two distinct modes of visual processing: an ambient mode, which is associated with overall spatial orientation in a scene, followed by a focal mode, which requires central vision of an object. However, the shifts between ambient and focal processing modes have mainly been identified relative to changes in the environment, such as relative to the onset of various visual stimuli but also following scene cuts or subjective event boundaries in dynamic stimuli. The results so far do not allow conclusions about the nature of the two processing mechanisms beyond the influence of externally triggered events. It remains unclear whether people shift back and forth from ambient to focal processing also based on internal triggers, such as switching between different tasks while no external event is given. The present study therefore investigated ambient to focal processing shifts in an active task solving paradigm. The Rubik's Cube task introduced here is a multi-step task, which can be broken down into smaller sub-tasks that are performed serially. The time course of eye movements was analyzed at multiple levels of this Rubik's Cube task, including when there were no external changes to the stimuli but when internal representations of the task were hypothesized to change (i.e., switching between different sub-tasks). Results suggest that initial ambient exploration is followed by a switch to more focal viewing across various levels of task processing with and without external changes to the stimuli. More importantly, the present findings suggest that ambient and focal eye movement characteristics might serve as a probe for the attentional state in task processing, which does not seem to be influenced by changes in task performance.

Investigating the utility of VR for spatial understanding in surgical planning: evaluation of head-mounted to desktop display.

Recent technological advances have made Virtual Reality (VR) attractive in both research and real world applications such as training, rehabilitation, and gaming. Although these other fields benefited from VR technology, it remains unclear whether VR contributes to better spatial understanding and training in the context of surgical planning. In this study, we evaluated the use of VR by comparing the recall of spatial information in two learning conditions: a head-mounted display (HMD) and a desktop screen (DT). Specifically, we explored (a) a scene understanding and then (b) a direction estimation task using two 3D models (i.e., a liver and a pyramid). In the scene understanding task, participants had to navigate the rendered the 3D models by means of rotation, zoom and transparency in order to substantially identify the spatial relationships among its internal objects. In the subsequent direction estimation task, participants had to point at a previously identified target object, i.e., internal sphere, on a materialized 3D-printed version of the model using a tracked pointing tool. Results showed that the learning condition (HMD or DT) did not influence participants' memory and confidence ratings of the models. In contrast, the model type, that is, whether the model to be recalled was a liver or a pyramid significantly affected participants' memory about the internal structure of the model. Furthermore, localizing the internal position of the target sphere was also unaffected by participants' previous experience of the model via HMD or DT. Overall, results provide novel insights on the use of VR in a surgical planning scenario and have paramount implications in medical learning by shedding light on the mental model we make to recall spatial structures.

Saccadic peak velocity sensitivity to variations in mental workload.

INTRODUCTION: For research and applications in the field of (neuro)ergonomics, it is of increasing importance to have reliable methods for measuring mental workload. In the present study we examined the hypothesis that saccadic eye movements can be used for an online assessment of mental workload. METHODS: Saccadic main sequence (amplitude, duration and peak velocity) was used as a diagnostic measure of mental workload in a virtual driving task with three complexity levels. We tested 18 drivers in the SIRCA driving simulator while their eye movements were recorded. The Wickens' multiple resources model was used as theoretical framework. Changes in mental workload between the complexity levels were evaluated multidimensionally, using subjective rating, performance in a secondary task, and other behavioral indices. RESULTS: Saccadic peak velocity decreased (7.2 visual degrees/s) as the mental workload increased, as measured by scores of mental workload test (15.2 scores) and the increase of the reaction time on the secondary task (46 ms). DISCUSSION: Saccadic peak velocity is affected by variations in mental workload during ecologically valid tasks. We conclude that saccadic peak velocity could be a useful diagnostic index for the assessment of operators' mental workload and attentional state in hazardous environments.

Size matters: How reaching and vergence movements are influenced by the familiar size of stereoscopically presented objects.

The knowledge about the usual size of objects-familiar size-is known to be a taken into account for distance perception. The influence of familiar size on action programming is less clear and has not yet been tested with regard to vergence eye movements. In two experiments, we stereoscopically presented everyday objects, such as a credit card or a package of paper tissues, and varied the distance as specified by binocular disparity and the distance as specified by familiar size. Participants had to fixate the shown object and subsequently reach towards it either with open or with closed eyes. When binocular disparity and familiar size were in conflict, reaching movements revealed a combination of the two depth cues with individually different weights. The influence of familiar size was larger when no visual feedback was available during the reaching movement. Vergence movements closely followed binocular disparity and were largely unaffected by familiar size. In sum, the results suggest that in this experimental setting familiar size is taken into account for programming and executing reaching movements while vergence movements are primarily based on binocular disparity.

Limitations of gaze transfer: without visual context, eye movements do not to help to coordinate joint action, whereas mouse movements do.

Remote cooperation can be improved by transferring the gaze of one participant to the other. However, based on a partner's gaze, an interpretation of his communicative intention can be difficult. Thus, gaze transfer has been inferior to mouse transfer in remote spatial referencing tasks where locations had to be pointed out explicitly. Given that eye movements serve as an indicator of visual attention, it remains to be investigated whether gaze and mouse transfer differentially affect the coordination of joint action when the situation demands an understanding of the partner's search strategies. In the present study, a gaze or mouse cursor was transferred from a searcher to an assistant in a hierarchical decision task. The assistant could use this cursor to guide his movement of a window which continuously opened up the display parts the searcher needed to find the right solution. In this context, we investigated how the ease of using gaze transfer depended on whether a link could be established between the partner's eye movements and the objects he was looking at. Therefore, in addition to the searcher's cursor, the assistant either saw the positions of these objects or only a grey background. When the objects were visible, performance and the number of spoken words were similar for gaze and mouse transfer. However, without them, gaze transfer resulted in longer solution times and more verbal effort as participants relied more strongly on speech to coordinate the window movement. Moreover, an analysis of the spatio-temporal coupling of the transmitted cursor and the window indicated that when no visual object information was available, assistants confidently followed the searcher's mouse but not his gaze cursor. Once again, the results highlight the importance of carefully considering task characteristics when applying gaze transfer in remote cooperation.

Gaze transfer in remote cooperation: is it always helpful to see what your partner is attending to?

Establishing common ground in remote cooperation is challenging because nonverbal means of ambiguity resolution are limited. In such settings, information about a partner's gaze can support cooperative performance, but it is not yet clear whether and to what extent the abundance of information reflected in gaze comes at a cost. Specifically, in tasks that mainly rely on spatial referencing, gaze transfer might be distracting and leave the partner uncertain about the meaning of the gaze cursor. To examine this question, we let pairs of participants perform a joint puzzle task. One partner knew the solution and instructed the other partner's actions by (1) gaze, (2) speech, (3) gaze and speech, or (4) mouse and speech. Based on these instructions, the acting partner moved the pieces under conditions of high or low autonomy. Performance was better when using either gaze or mouse transfer compared to speech alone. However, in contrast to the mouse, gaze transfer induced uncertainty, evidenced in delayed responses to the cursor. Also, participants tried to resolve ambiguities by engaging in more verbal effort, formulating more explicit object descriptions and fewer deictic references. Thus, gaze transfer seems to increase uncertainty and ambiguity, thereby complicating grounding in this spatial referencing task. The results highlight the importance of closely examining task characteristics when considering gaze transfer as a means of support.

I see you remembering: what eye movements can reveal about process characteristics of prospective memory.

Prospective memory performance describes the delayed execution of an intended action. As this requires a mixture of memory and attentional control functions, current research aims at delineating the specific processes associated with solving a prospective memory task. Therefore, the current study measured, analysed and compared eye movements of participants who performed a prospective memory, a free viewing, and a visual search task. By keeping constant the prospective memory cue as well as the context of tasks, we aimed at putting the processes of solving prospective memory tasks into context. The results show, that when a prospective memory task is missed, the continuous gaze behaviour is rather similar to the gaze behaviour during free viewing. When the prospective memory task is successfully solved, on the other hand, average gaze behaviour is between free viewing and visual search. Furthermore, individual differences in eye movements were found between low and high performers. Our data suggest that a prospective memory task can be solved in different ways, therefore different processes can be observed.

Comparing two types of engineering visualizations: task-related manipulations matter.

This study focuses on the comparison of traditional engineering drawings with a CAD (computer aided design) visualization in terms of user performance and eye movements in an applied context. Twenty-five students of mechanical engineering completed search tasks for measures in two distinct depictions of a car engine component (engineering drawing vs. CAD model). Besides spatial dimensionality, the display types most notably differed in terms of information layout, access and interaction options. The CAD visualization yielded better performance, if users directly manipulated the object, but was inferior, if employed in a conventional static manner, i.e. inspecting only predefined views. An additional eye movement analysis revealed longer fixation durations and a stronger increase of task-relevant fixations over time when interacting with the CAD visualization. This suggests a more focused extraction and filtering of information. We conclude that the three-dimensional CAD visualization can be advantageous if its ability to manipulate is used.

The effects of self-involvement on attention, arousal, and facial expression during social interaction with virtual others: a psychophysiological study.

Social neuroscience has shed light on the underpinnings of understanding other minds. The current study investigated the effect of self-involvement during social interaction on attention, arousal, and facial expression. Specifically, we sought to disentangle the effect of being personally addressed from the effect of decoding the meaning of another person's facial expression. To this end, eye movements, pupil size, and facial electromyographic (EMG) activity were recorded while participants observed virtual characters gazing at them or looking at someone else. In dynamic animations, the virtual characters then displayed either socially relevant facial expressions (similar to those used in everyday life situations to establish interpersonal contact) or arbitrary facial movements. The results show that attention allocation, as assessed by eye-tracking measurements, was specifically related to self-involvement regardless of the social meaning being conveyed. Arousal, as measured by pupil size, was primarily related to perceiving the virtual character's gender. In contrast, facial EMG activity was determined by the perception of socially relevant facial expressions irrespective of whom these were directed towards.