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 @ ) ; 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 ( @ % , @ % , @-point , or @-point change in score from screening to week @ ) for each item and subscale .