Statistical analyses examined treatment arm differences ( BTDS vs placebo ) for the following : BPI Interference subscale items and subscale scores at the trial end point ( week 12 ) ; patterns of change in the Interference subscale scores over time ; proportions of patients indicating mild or no interference following treatment ; and proportions of patients showing improvement ( 30 % , 50 % , 2-point , or 4-point change in score from screening to week 12 ) for each item and subscale .