No one is really sure yet what the relationship is between complex regional pain syndrome (CRPS) and dystonia (a movement disorder). Both seem to occur after a traumatic injury. They don’t always develop at the same time but dystonia does seem to come after CRPS. Sometimes people with CRPS never have any of the many movement disorders possible.
Other reports of the abnormal postures persisting during sleep have been published. EMG (electromyographic) studies have been done. The affected muscles were tested during the various phases of sleep. Despite the fact that the hand position stayed the same, the EMG activity was not continuous as might be expected.
Researchers aren’t quite sure what to make of all that. They suspect the circuits of the nervous system are not balanced. Perhaps some pathways got turned on and stuck in the on position. If trauma is what ignites these two conditions, how is the fuse lit in the first place? That’s the question facing many scientists as they search for answers to this perplexing problem.
Most agree that it is not a psychiatric or emotional problem. The nervous system is the problem area but the exact mechanism is still unknown.