| 1. |
- Britt, Rebecca C, et al.
(författare)
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Intracorporeal suturing: Transfer from Fundamentals of Laparoscopic Surgery to cadavers results in substantial increase in mental workload
- 2015
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Ingår i: Surgery. - : Elsevier. - 0039-6060 .- 1532-7361. ; 158:5, s. 1428-1433
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION:A spatial secondary task developed by the authors was used to measure the mental workload of the participant when transferring suturing skills from a box simulator to more realistic surgical conditions using a fresh cadaver. We hypothesized that laparoscopic suturing on genuine bowel would be more challenging than on the Fundamentals of Laparoscopic Surgery (FLS)-simulated bowel as reflected in differences on both suturing and secondary task scores.METHODS:We trained 14 surgical assistant students to FLS proficiency in intracorporeal suturing. Participants practiced suturing on the FLS box for 30 minutes and then were tested on both the FLS box and the bowel of a fresh cadaver using the spatial, secondary dual-task conditions developed by the authors.RESULTS:Suturing times increased by >333% when moving from the FLS platform to the cadaver F(1,13) = 44.04, P < .001. The increased completion times were accompanied by a 70% decrease in secondary task scores, F(1,13) = 21.21, P < .001.CONCLUSION:The mental workload associated with intracorporeal suturing increases dramatically when trainees transfer from the FLS platform to human tissue under more realistic conditions of suturing. The increase in mental workload is indexed by both an increase in suturing times and a decrease in the ability to attend to the secondary task.
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| 2. |
- Prytz, Erik, et al.
(författare)
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Changes in stress and subjective workload over time following a workload transition
- 2015
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Ingår i: Theoretical Issues in Ergonomics Science. - 1463-922X .- 1464-536X. ; 16:6, s. 586-605
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Tidskriftsartikel (refereegranskat)abstract
- Workload transitions present individuals with sudden changes in workload. These transitions may affect stress and coping behaviour. Two experiments were performed using a digit detection task that shifted between low and high workload levels to examine transition effects on performance, stress, and effort. The first experiment used a large magnitude transition and resulted in decreased estimates of task engagement and effort. Over time, the levels of subjective stress observed in the transitioned groups approached those of the non-transitioned control groups. The second experiment used a transition more moderate in magnitude. The results were similar to those from the first experiment except that the transition resulted in higher, sustained task engagement and effort. These findings indicate that over time, the perceived stress of transitioned individuals will approach those of non-transitioned individuals; however, the magnitude of the transition may influence individuals to either increase or decrease task-oriented, effortful coping.
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| 3. |
- Prytz, Erik, et al.
(författare)
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Laparoscopic Skill and Mental Workload Measured over Retention Interval
- 2016
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Ingår i: Abstracts to be Presented at the 16th Annual International Meeting on Simulation in Healthcare: January 16th – 20th, 2016 San Diego, CA.
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Konferensbidrag (refereegranskat)abstract
- Methods: Fourteen students (3 males, 12 females; ages 23Y28 years) from EasternVirginiaMedical School’sMaster of Surgical Assisting Program participated in this IRBapproved study. Participants practiced the peg transfer task from the FLS curriculum ona box simulator for 20Y30 minutes over 9Y15 weekly sessions. Their course schedulerequired all students to stop training after the 15th week irrespective of their performancelevel. They returned after a 1-month interval to resume training. The dependentmeasure was task completion time. The secondary task presented images of four balls ina simulated tunnel, superimposed at 50% transparency over the laparoscopic display sothat both tasks were in focal vision. Images were presented for 300 msec every 2Y4 sec.On half of the presentations, one ball changed its position. Participants had to detectthose changes by pressing a foot pedal. The dependent variables were the proportion ofcorrectly identified targets and false alarms.Hypothesis: Performing laparoscopy places heavy demands on visual attention andrequires extensive practice to achieve proficiency. Recently, some researchers havemeasured the mental workload imposed by laparoscopy using the secondary tasktechnique.1,2 According to multiple resource theory, pools of attentional resources aredistinguished by perceptual/cognitive processing stages, verbal and spatial processingcodes, and sensory modality with the vision separated into focal and peripheralchannels.3 Thus, a secondary task that competes for the same resources as a primarytask will cause interference and can be sensitive to differences in mental workload. Inthis study,mental workload was assessed with a secondary task that uses the same visualspatial resources as laparoscopy.We studied effects of refraining from practice during a1-month interval. We expected to see a decline in performance after the delay, but ourgoal was to see if decline would be present in the workload measure.Results: Three sets of tests were performed: the data for the last two training trials (Nand N-1), the last training trial (N) and the initial retention test after the delay interval,and the initial retention test vs. a final test after 30 minutes of retraining (see Table 1).All means were evaluated with dependent t tests (alpha = .05). There were no differencesbetween the last two training trials on any measure. The peg task completiontimes were significantly longer on the initial test compared to the last training trial,t(13) = 2.36, p G .05. There were no differences between the initial and final test on anymeasure (p 9 .05).Conclusion: The results show minimal effects on the peg transfer task from the FLSprogram over a 1-month retention interval. Mean completion times were significantlylonger after the delay interval, but only by 6 seconds (or less than 10%). There were nosignificant differences on the secondary task. Thus, the slower performance times werenot accompanied by any appreciable changes in mental workload. These results showthat 9 Y 15 training sessions were sufficient to establish robust skills for the peg transfertask and that these skills were fairly resilient to a moderate disruption in the trainingschedule. Further, the secondary task used in this study was shown to provide an alternativeindex of laparoscopic workload that can complement traditional metrics ofspeed and accuracy. Future research is needed to examine disruption effects over awider range of laparoscopic tasks and longer intervals.
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| 4. |
- Prytz, Erik, et al.
(författare)
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Spatial Judgments from Different Vantage Points: A Different Perspective
- 2011
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Ingår i: Proceedings of the Human Factors and Ergonomics Society Annual Meeting. - : Sage Publications. - 1541-9312. ; , s. 1274-1278
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Konferensbidrag (refereegranskat)abstract
- Todorovic (2008) reported that there are systematic errors in the perception of 3-D space when viewing 2-D linear perspective drawings depending on the observer’s vantage point. Because Todorovic’s findings were restricted to the horizontal plane, the current study was designed to determine whether the magnitude of these errors would be similar in the vertical plane. Participants viewed a 2D image containing rows of columns aligned on parallel converging lines receding to a vanishing point. They were asked to judge where in the physical room the next column should be placed. The results support Todorovic (2008) in that systematic deviations in the spatial judgments depended on vantage point for both the horizontal and vertical planes. However, the pattern of deviation differed between the two planes. While judgments in both planes failed to compensate adequately for the vantage point shift, the vertical plane induced greater distortions of the stimulus image itself within each vantage point.
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| 5. |
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| 6. |
- Prytz, Erik, et al.
(författare)
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The effects of a workload transition on stress over time
- 2014
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Ingår i: Proceedings of the Human Factors and Ergonomics Society. - : Human Factors an Ergonomics Society Inc.. - 2169-5067 .- 1071-1813. - 9780945289456 ; , s. 1766-1770
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Konferensbidrag (refereegranskat)abstract
- The present study explored the effects of a workload transition on three dimensions of stress: task engagement, distress, and worry. Previous research on the effects of workload transitions has generated conflicting results. It was suggested that the concept of a continuous stress appraisal process could potentially resolve these prior conflicting results. A digit-processing task with high and low task demands was used to test this suggested explanation. Subjective reports of stress were measured both one minute and six minutes posttransition to show changes over time. The results showed that a workload transition affects each of the three stress dimensions differently such that task engagement declined over time, distress decreased following a high-to-low transition six minutes posttransition, and worry increased following a transition. These results suggest that distress and worry are more sensitive to workload transitions than task engagement. Further, the appraisal process may partially explain the prior conflicting findings by accounting for changes in stress over time.
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| 7. |
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| 8. |
- Prytz, Erik, et al.
(författare)
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Using Fitts’ Law for a 3D Pointing Task on a 2D Display: Effects of Depth and Vantage Point
- 2012
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Ingår i: Proceedings of the Human Factors and Ergonomics Society Annual Meeting. - : Sage Publications. - 2169-5067. ; , s. 1391-1395
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Konferensbidrag (refereegranskat)abstract
- Laparoscopic surgery requires surgeons to make judgments about three-dimensional movements using a two-dimensional display. This arrangement reduces the available visual feedback information, such as certain depth cues. The current study used Fitts’ (1954) law to examine the relationship between psychomotor movement time, target size and target distance for a psychomotor pointing task using a laparoscopic instrument in three-dimensional space projected on a two-dimensional display from different vantage points. Analyses demonstrate an effect for depth of target on accuracy, internal consistency and movement time. The results demonstrate that Fitts’ law can be utilized to detect differences in conditions when a three-dimensional task must be completed with the visual feedback presented on a two-dimensional display. No reliable results of vantage point were found. Thus, the location of a two-dimensional display may not be critical for the type of laparoscopic pointing tasks examined in the present study.
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| 9. |
- Prytz, Erik, 1985-
(författare)
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Workload transitions and stress : changes over time
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Workload transitions are situations where operators are suddenly confronted with levels of workload substantially different from previously established levels. Workload transitions may affect the operators' state of stress and coping behaviors but previous research has not conclusively demonstrated the nature of those. The first goal of the current work was to investigate the discrepant findings of the previous literature. Two experiments were conducted where participants were asked to perform a digit detection task that suddenly shifted between low and high event rates (i.e., low and high workload, respectively). The first experiment used a large magnitude transition that resulted in a decrease in reported levels of task engagement and effort. Over time, the reported stress and workload ratings of the transitioned groups approached the nontransitioned control groups. A second experiment was conducted using a moderate magnitude transition. This second experiment replicated the findings from the first experiment, with the key difference being that the transition from a low to more a more moderate level of workload resulted in higher, sustained task engagement and effort. Two main conclusions are drawn from these results. First, over time the stress and workload levels of individuals who experience a transition will approach those reported by nontransitioned individuals. Future workload transition research must therefore consider the effect of the time from transition. Second, the magnitude of the transition may influence the coping response such that a moderate transition may result in increased task-oriented, effortful coping whereas a large magnitude transition may result in decreased effortful coping.
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| 10. |
- Rebecca, Kennedy, et al.
(författare)
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The Influence of Visual Aids on Detecting Early and Late Decelerations in Maternal-Fetal Heart Rate Patterns
- 2012
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Ingår i: PROCEEDINGS of the HUMAN FACTORS and ERGONOMICS SOCIETY 56th ANNUAL MEETING. - : SAGE Publications. - 2169-5067 .- 1071-1813. ; , s. 1317-1321
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Konferensbidrag (refereegranskat)abstract
- The present study examined how well individuals could differentiate between two different types of signals (early and late decels) in maternal-fetal heart rate tracings with and without the use of a visual aid. Twenty-one undergraduates twice viewed 80 simulated images under four different signal-to-noise (S/N) ratios. Further, the late decels were delayed in 4-sec increments. In one block of trials, the images were presented without a visual aid, and in the other block a visual aid consisting of a large turquoise crosshair was overlaid on the images. The results indicated that lower S/N ratios and shorter onset delays made signals more difficult to distinguish. However, overall levels of accuracy were significantly higher when the visual aid was present. These results provide initial evidence that utilizing visual aids can enhance the ability to detect critical signals in maternal-fetal heart rate patterns.
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