My phd hubby has moderate Chorea. Within the past few months his right hand has started to "flex" up at the wrist and turned to a slow writhing flex & he is not able to use the hand as much. This is new & we are just wondering if this has a name, is this what dystonia is?

i know dystonia refers to muscle tone ect. I think you may be right in thinking his movements are a form of dystonia: i would probably ask the dr about it - that way, if there is any help he can have in terms of physio or even basic advice as to anything may make him more comfortable.
Dystonic reactions can sometimes occur as a result of certain psychotropic medications (ie side effects) but, in my experience this is only really associated with some of the "older" style drugs that were commonly used in the 80s and 90s. And the reaction was more just about having a "stony face" or severe reaction within the neck/trunk as opposed to the writhing movements/muscle contractions you are describing.
Also, in terms of side effects, i have not seen that occur in someones hands.
So, i think its back to your original question: is it dystonia: possibly - ask dr. x x x

There seem to be some tell tale arm and hand movements that are common. It sounds from your description its what I have seen .. by words I couldn't have described it any better. I don't know if there is much to be done about it. I haven't asked if it's been treated but I will one Monday and see what they say here. My wife does a different thing with her hand, which the physical therapist did try a a wrist and arm brace to help "retrain" it but it didn't help noticeably in her case. It would look as if her hand and wrist would be locked in this position which was the worry as she too didn't use that hand as much.. but it actually has not done this either. the hand has always opened nicely for washing or whatever. Anyway I will locate one of the people who have what you are talking about and see if have any treatment for it that is tried. Since I see it though.. I am guessing they don't have much for it or I wouldn't see it.

Thank you both for your responses. It's just one of those little things that we notice is "new" in this process. I thought it was just a little different than the normal chorea movements.

Eric, thanks. I'll look forward to hearing if you find out any more.