UPDRS items 32 + 33 deteriorated more in patients switched to placebo ( `` discontinuing '' group ) ( +1.7 2.0 units ; 95 % confidence interval 0.9 , 2.4 ) as compared with those maintained on amantadine ( `` continuing '' group ) ( +0.2 1.5 units ; 95 % confidence interval -0.4 , 0.8 ; p = 0.003 ) .