Movement disorders in complex regional pain syndrome.

About 25% of the patients with complex regional pain syndrome (CRPS) suffer movement disorders, including loss of voluntary control, bradykinesia, dystonia, myoclonus, and tremor. These movement disorders are generally difficult to manage and add considerably to the disease burden. Over the last years, interesting findings have emerged that show how tissue or nerve injury may induce spinal plasticity (central sensitization), which alters sensory transmission and sensorimotor processing in the spinal cord and is associated with disinhibition. These changes, in turn, set the stage for the development of movement disorders seen in CRPS. There are no randomized control studies on the treatment of movement disorders in CRPS but findings from fundamental and clinical research suggest that strategies that enhance the central inhibitory state may benefit these patients.