What I consider to be dystonia is a muscle that contracts tighter and tighter and won't release. Hurts like hell and decides to let go when it darn well suits itself. Mine shows up in the morning when I first try to walk and twists my feet and stiffens my legs. It is asymmetrical and affects my left leg more than my right even though my PD is dominant on my right. I sort of hobble and skate to my chair, take my meds, and wait. In about 15 minutes the problem dissolves away.

Because this occurs in the early part of my day and when I first get up (whether that be 4 AM or 7 AM) I often suspect that it is related to the surge of chemicals that occurs at that time (e.g. adrenaline, noradrenaline, etc).

But I have another suspect, as well. Dehydration can cause monstrous cramping and, because I use a bedside urinal, I am very much aware of fluid loss and there does seem to be a connection. Dehydration is more than just water loss. It includes problems with electrolytes such as potassium and water soluble B-vitamins. Both those are further depleted by the use of sinemet, as well. You might try those two plus some magnesium just before you would normally expect to develop problems. If it makes *any* change that could be an important clue. Good luck.