AS some of us suffer from Functional Dystonia, this can be really helpful. additionally anyone who suffers from the involuntary muscle spasms, this may help answer questions for you too.
Here is a link to The Dystonia Society website, that has the link to Dr Tom Warner.
He has very kindly answers lots of questions, and gives great answers in an understandable way.
Here is the question list, and time points you will find them.