Dew,
Diana really nailed it spot on.
The ins. company has the right to do this. You can look at it in two ways, they're looking for loopholes, or holes in the doctors story, or, if they're a decent ins. company, they owe it to their stockholders to prove out every claim they pay.
There are far too many malingerers who take advantage, and all they want to do is be sure you're not one.
In the age of the internet, it's easier to come to a place like this and "read the symptoms" of even a strange disease like RSD.

If you trust your doctor, you've nothing to worry about.
You know yourself, your symptoms etc. so, like Diana says, just stay calm, and even if you're not calm, they rile your symptoms if they depose you. And, they'll show.
Either way, unless your doctor is a twirp, your can't really lose.
If you have an attorney, s/he should be there!

Pete
asb