The Effect of Depth Judgments on Mental Workload in Laparoscopy Measured by a Visual-Spatial Secondary Task

Performing laparoscopic surgery is more attentionally demanding than traditional surgery. One challenge results from the surgeon operating in 3D space while referencing a 2D display that has limited and distorted depth cues. The goal of the present study was to compare two versions of a secondary task for measuring the mental workload associated with laparoscopic depth and nondepth movements. Twenty six undergraduate students at Old Dominion University performed a laparoscopic threading task in three separate orientations: X plane, Y plane, and Z plane. The threading task was performed in single-task conditions and dual-task conditions where it was paired with a visual-spatial secondary task to measure workload. It was expected that workload would be highest when threading in the Z plane orientation, reflecting challenges for making depth judgments based on a 2D display. The primary task results showed that participants indeed had difficulty performing the threading task when depth judgments were required. The secondary task was sensitive to overall laparoscopic workload, but was not found to be sensitive to the specific differences in workload for threading orientation. There were also no performance differences between versions of the secondary task. The findings suggest that laparoscopic surgery is attentionally demanding and surgical training should emphasize practicing movements in the depth plane.