Govert Veldhuijzen

42 Chapter 2 maintain the focus of patient. Patient interaction was ascertained by a mandatory mouse-click after each item in the CAI. All informative elements, especially mandatory for informed consent for colonoscopy (risks, alternatives) were included. Figure 2. Several screenshots from the computer assisted instruction (the persons in these stills are actors) Outcomes The primary outcome was cleanliness of the colon during examination as assessed by the OBPS and the BBPS. The secondary outcomes were patient comfort with the received information, anxiety and knowledge and comprehension. Statistical analyses A sample size of 322 provides 80% power, with a two-tailed α of 0.05, to detect an increase in the primary outcome measure (BBPS) from 6.0 in the control group to 6.5 in the experimental group, with a standard deviation of 1.6. All analyses were performed using SPSS version 20.0 for Windows (SPSS Inc., Chicago, IL, USA). We used descriptive statistics to describe baseline information including frequency count, percentage and mean ±standard deviation. Further analyses included the chi-square test, independent t-test and Mann-Whitney. P-values under 0.05 were regarded statistically significant. Registration number The trial was registered in ClinicalTrials.gov with number: NCT02656602 Ethical considerations The study was approved by the institutional review board of the Medical Center Alkmaar.