They performed @ practice trials after being randomly allocated to @ of @ experimental groups : training with ( @ ) the paretic arm with direct view ( Paretic-No Mirror ) , ( @ ) the nonparetic arm with direct view ( Nonparetic-No Mirror ) , ( @ ) the nonparetic arm with mirror reflection ( Nonparetic Mirror ) , ( @ ) both sides and with a nontransparent screen preventing visual control of paretic side ( Bilateral-Screen ) , and ( @ ) both sides with mirror reflection of the nonparetic arm ( Bilateral-Mirror ) .