Alan Stubbs said: "You can see the difference in him since he's been going to see this man he goes to.
"He feels better in himself physically, and psychologically it probably helps, too.
"He was probably wondering why things were happening all the time to him and why he was picking up injuries as much as he did, but now someone is hopefully sorting it out for him he can see the benefits himself. And so can we."
Ferguson was handed the captain's armband by new boss David Moyes, and Stubbs added: "Duncan's good for the lads before the game. He gets all the lads motivated.
"He did that anyway, but now he's got the captain's armband he does it even more."