# The Effects of 3D and 2D Imaging on Brain Wave Activity in Laparoscopic Training
## 4 Discussion  
Visual dimensions had a significant effect on both surgery-related parameters, namely, completion time and precision, in the two dimensional laparoscopic tasks in this study. In the depth-perception peg transfer task, the mean completion time was significantly shorter with the 3D vision system than with the 2D system. This result is in line with most of the studies published to date [14]. This finding suggests that, in tasks requiring depth perception, a modern 3D vision system that provides high-resolution images may improve task performance, even if the task requires much time to complete [28]. In contrast, in the circle-tracing task, which does not require depth perception, the mean completion time was significantly shorter with the 2D system than with the 3D system. Early studies reported that there were no significant differences in the completion times of this type of task when 2D and 3D systems were used [52], and recent research has indicated that the 3D system confers an operating time advantage even on easy tasks [14; 53]. Therefore, the finding of a longer manipulation time in this study contradicts previous findings. In the pegboard task, the 3D condition provided significantly better performance than the 2D condition in terms of mean error frequency. Previous studies have ascribed this increased precision to the better depth perception provided by the 3D system [14; 54; 55]. However, in the 2D circle-tracing task, there were no significant differences in mean error frequency between the image vision systems. In this study, the MUSE headband with its EEG function was used as a direct measure of cortical activity during laparoscopic simulations. This is in stark contrast to previously mentioned surrogate measures, which, instead of directly measuring brain activity, require downstream extrapolations. Gamma waves are associated with concentration, thought, and listening, while alpha waves reflect a state of a calm and balanced psychological state [56]. The results of this study indicated no significant differences in EEG alpha wave activity between the simulated laparoscopic tasks or vision systems. However, a significant interaction of simulated task \(\times\) vision system was found. In the peg transfer task, EEG alpha wave activity was significantly higher in the 3D condition than in the 2D condition. This finding implies that participants experienced less stress with the 3D vision system while performing a depth perception task. In terms of EEG gamma wave activity, there were no significant differences between the two tasks, but significant main effects of the vision systems and an interaction of simulated task \(\times\) vision system were found. These findings demonstrated that participants maintained a higher state of attentiveness with the 2D vision system in both levels of the simulated laparoscopic tasks with depth perception. A strong advantage of using the blink rate to assess surgeons' mental workload is that this technology allows continuous monitoring of changes in the mental status of the surgeon during a surgical procedure [44]. Reduction of blink frequency is associated with higher levels of mental workload [44; 50; 51]. In the present study, participants perceived a higher mental workload with the 2D vision system than with the 3D system and when performing the depth-perception task, as indicated by the lower blink frequency. The subjective workload experienced by the participants was significantly reduced in three of the six NASA TLX weightings, indicating that the 3D vision system was not only tolerated but was better tolerated than the standard 2D system in terms of mental demand, satisfaction with performance and frustration. These findings indicated that participants required more mental and perceptual activity (decision-making, memory, and searching) and experienced higher levels of effort on performance and greater frustration when completing the tasks with the 2D vision system.