Re: Captain America 2: News and Speculation - Part 1
The bump to the head thing could work, given it presumably took a lot of brainwashing for Bucky to become the Winter Soldier. He could definitely be subject to painful flashbacks (i.e. like Banner is in the Incredible Hulk) at inopportune moments.
Maybe it gets worse for him in a fight with Cap/Crossbones when he gets hit (it's not that likely he'll have taken too many of them in his preceding WS years as he's essentially used as a surprise assassin and often takes targets out on the sly or from distance).
And perhaps his mind really starts to return after a strike from the good old vibranium. Even after brainwashing, he's got to have some subconscious memory of how dangerous a man throwing a big metal shield about is? Surely?