Sample size and randomization
The sample size was calculated based on the primary end point. Assuming a difference in the mean overall scores between the groups of 15 with a standard deviation of 10 according to our unpublished data, this study required a total sample size of 20 participants (10 participants for each group) to achieve a power of 90% and an alpha error of 5% (two-sided).Randomization was performed by the principal investigator using a random number (Excel RAND) function. The participants were randomly divided into two groups: video and control.