Below is a Youtube link of Michael J Fox not being as jerky as he was in the polictical commercials(i.e taking his medication).
Link.
The clips storyline is kinda of creepy(i.e it's about a "funeral" party for MJF's character). I don't watch Boston Legal but notice at the end of the clip at the dramatic closing where MJF is not jerking around at all.
There's been at least two episodes after that one that he's been on the show.
He was on the end of last season and I think two of this current season.