# The Effects of 3D and 2D Imaging on Brain Wave Activity in Laparoscopic Training
## 1 Introduction  
The past two decades have seen the development of laparoscopy and improved outcomes in patients receiving surgeries due to the minimization of surgical trauma, acceleration of postoperative recovery, and abbreviation of hospital stays [1, 2, 3, 4]. However, laparoscopic surgery is more challenging than open laparotomy due to the differences in the psychomotor skills required. One challenge is that the surgeons must complete tasks within three-dimensional (3D) spaces while depending on two-dimensional (2D) images [5, 6]. The consequent lack of depth perception and spatial orientation increases the visual and cognitive loads of the tasks [7, 8, 9]. The overall goals of such a surgical procedure comprise two main components (i.e., a primary and a secondary task). The former is simply the performance of the physical steps of the procedure with instruments and visual feedback. The latter is more complicated, as it is the decision-making on the strategies to be used and steps to be executed. The primary task can be unusually difficult due to the extremely limited cognitive resources for overall monitoring and planning, which may delay the detection of an evolving problem until it becomes an emergency [10]. Increased workload is associated with inferior task performance and higher likelihood of errors [11]. One goal in training and instrument design is to ensure that the surgeon's movements are both accurate and efficient. Another should be to decrease the mental workload of the surgeon performing the primary surgical task while maintaining acceptable performance levels [10]. 3D laparoscopy was developed as an alternative to conventional 2D laparoscopy to overcome some of the challenges associated with laparoscopy [4; 9; 12; 13]. In 3D laparoscopy, image magnification and direct illumination are combined to synthesize left- and right-eye images from a two-channel 3D laparoscope so as to approximate closely what a surgeon would see if they were positioned at the end of the laparoscope [14]. Stereoscopic 3D laparoscopy provides great advantages, particularly when surgery is being performed in areas such as the male pelvis, which can be difficult to visualize. Compared to 2D laparoscopy, 3D laparoscopy has been reported to improve speed and reduce the number of performance errors, and it has resulted in significantly reduced surgical time, blood loss, perioperative complications, and hospital stays among patients who received abdominal surgery in simulated and clinical settings, respectively [14; 15; 16]. The stereoscopic vision provided by 3D laparoscopy improves task precision and reduces task performance time due to the simpler presentation of anatomical structures and greater depth perception. Using high-definition 3D vision during training, surgeons can quickly enhance their surgical skills, with the result that the learning curve in simulated settings can be greatly reduced [17]. In fact, for both experienced and inexperienced surgeons, training programs employing 3D systems provide improved task efficiency, error reduction, and accelerated acquisition of basic thoracoscopic and laparoscopic skills [18]. As above-mentioned, interest in the measurement of surgical skill and performance in laparoscopy has been increasing, especially as these are related to the evaluation of training [19; 20; 21]. Although the use of performance efficiency measures (speed, movement economy, errors) and ergonomic assessments are relatively well established, however, fewer systematic attempts have been made to develop standardized measures for evaluating the cognitive outcomes of technological innovations. The most important benefit of using 3D vision systems is improved depth perception, which may reduce the surgeon's mental workload [14; 22]. Several recent studies have used the National Aeronautics and Space Administration Task Load Index (NASA-TLX) [23] to compare mental workload when using either 2D or 3D vision during laparoscopic surgery, and the results have been contradictory.