Expert and construct validity of the Simbionix GI Mentor II endoscopy simulator for colonoscopy

Objectives: The main objectives of this study were to establish expert validity (a convincing realistic representation of colonoscopy according to experts) and construct validity (the ability to discriminate between different levels of expertise) of the Simbionix GI Mentor II virtual reality (VR) simulator for colonoscopy tasks, and to assess the didactic value of the simulator, as judged by experts. Methods: Four groups were selected to perform one hand-eye coordination task (EndoBubble level 1) and two virtual colonoscopy simulations on the simulator; the levels were: novices (no endoscopy experience), intermediate experienced (< 200 colonoscopies performed before), experienced (200-1,000 colonoscopies performed before), and experts (> 1,000 colonoscopies performed before). All participants filled out a questionnaire about previous experience in flexible endoscopy and appreciation of the realism of the colonoscopy simulations. The average time to reach the cecum was defined as one of the main test parameters as well as the number of times view of the lumen was lost. Results: Novices (N = 35) reached the cecum in an average time of 29: 57 (min: sec), intermediate experienced (N = 15) in 5:45, experienced (N = 20) in 4: 19 and experts (N = 35) in 4:56. Novices lost view of the lumen significantly more often compared to the other groups, and the EndoBubble task was also completed significantly faster with increasing experience (Kruskal Wallis Test, p < 0.001). The group of expert endoscopists rated the colonoscopy simulation as 2.95 on a four-point scale for overall realism. Expert opinion was that the GI Mentor II simulator should be included in the training of novice endoscopists (3.51). Conclusion: In this study we have demonstrated that the GI Mentor II simulator offers a convincing realistic representation of colonoscopy according to experts (expert validity) and that the simulator can discriminate between different levels of expertise (construct validity) in colonoscopy. According to experts the simulator should be implemented in the training programme of novice endoscopists.