title: Using motion capture to assess colonoscopy experience level.
abstract: OBJECTIVE
  To study technical skills of colonoscopists using a Microsoft Kinect™ for motion analysis to develop a tool to guide colonoscopy education.
  
  
  RESULTS
  Ten experienced endoscopists (gastroenterologists, n = 2; colorectal surgeons, n = 8) and 11 novices participated in the study. A Microsoft Kinect™ recorded the movements of the participants during the insertion of the colonoscope. We used a modified script from Microsoft to record skeletal data. Data were saved and later transferred to MatLab for analysis and the calculation of statistics. The test was performed on a physical model, specifically the "Kagaku Colonoscope Training Model" (Kyoto Kagaku Co. Ltd, Kyoto, Japan). After the introduction to the scope and colonoscopy model, the test was performed. Seven metrics were analyzed to find discriminative motion patterns between the novice and experienced endoscopists: hand distance from gurney, number of times the right hand was used to control the small wheel of the colonoscope, angulation of elbows, position of hands in relation to body posture, angulation of body posture in relation to the anus, mean distance between the hands and percentage of time the hands were approximated to each other.
  
  
  RESULTS
  Four of the seven metrics showed discriminatory ability: mean distance between hands [45 cm for experienced endoscopists (SD 2) vs 37 cm for novice endoscopists (SD 6)], percentage of time in which the two hands were within 25 cm of each other [5% for experienced endoscopists (SD 4) vs 12% for novice endoscopists (SD 9)], the level of the right hand below the sighting line (z-axis) (25 cm for experienced endoscopists vs 36 cm for novice endoscopists, P < 0.05) and the level of the left hand below the z-axis (6 cm for experienced endoscopists vs 15 cm for novice endoscopists, P < 0.05). By plotting the distributions of the percentages for each group, we determined the best discriminatory value between the groups. A pass score was set at the intersection of the distributions, and the consequences of the standard were explored for each test. By using the contrasting group method, we showed a discriminatory value of Z = 1.51 to be the pass/fail value of the data showing discriminatory ability. The pass score allowed all ten experienced endoscopists as well as five novice endoscopists to pass the test.
  
  
  CONCLUSIONS
  Identified metrics can be used to discriminate between experienced and novice endoscopists and to provide non-biased feedback. Whether it is possible to use this tool to train novices in a clinical setting requires further study.
authors.affiliation: Morten Bo Svendsen, Lars Konge, Centre for Clinical Education, University of Copenhagen and the Capital Region of Denmark, 2100 Copenhagen, Denmark.
authors.forename: Morten Bo
authors.initials: MB
authors.lastname: Svendsen
authors.affiliation: Morten Bo Svendsen, Lars Konge, Centre for Clinical Education, University of Copenhagen and the Capital Region of Denmark, 2100 Copenhagen, Denmark.
authors.forename: Louise
authors.initials: L
authors.lastname: Preisler
authors.affiliation: Morten Bo Svendsen, Lars Konge, Centre for Clinical Education, University of Copenhagen and the Capital Region of Denmark, 2100 Copenhagen, Denmark.
authors.forename: Jens Georg
authors.initials: JG
authors.lastname: Hillingsoe
authors.affiliation: Morten Bo Svendsen, Lars Konge, Centre for Clinical Education, University of Copenhagen and the Capital Region of Denmark, 2100 Copenhagen, Denmark.
authors.forename: Lars Bo
authors.initials: LB
authors.lastname: Svendsen
authors.affiliation: Morten Bo Svendsen, Lars Konge, Centre for Clinical Education, University of Copenhagen and the Capital Region of Denmark, 2100 Copenhagen, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Konge
keywords: Assessment; Colonoscopy; Motion-analysis; Motion-capture; Simulation