In the ITT analyses , participants showed significant improvement in bowel symptoms as measured by the PAC-SYM ( mean SD , -@ @ , range : -@ -@ ) and PAC-QOL ( mean SD , @ @ , range : -@ -@ ) over time , but there were no significant differences between the lubiprostone and Senna groups in mean change in the PAC-SYM ( -@ @ vs -@ @ , P = @ respectively ) or the PAC-QOL ( @ @ vs @ @ , P = @ respectively ) .