Cortical reorganization during recovery from complex regional pain syndrome

OBJECTIVE: To characterize reorganization of the primary somatosensory cortex (S1) during healing process in complex regional pain syndrome (CRPS). BACKGROUND: Recently, the authors showed extensive reorganization of the S1 cortex contralateral to the CRPS affected side. Predictors for these plastic changes were CRPS pain and the extent of mechanical hyperalgesia. It is unclear how these S1 changes develop following successful therapy. METHODS: The authors used magnetic source imaging to explore changes in the cortical representation of digits (D) 1 and 5 in relation to the lower lip on the unaffected and affected CRPS side in 10 patients during a year or more of follow-up. RESULTS: Cortical reorganization reversed coincident with clinical improvement. A reduction of CRPS pain correlated with recovery from cortical reorganization. CONCLUSIONS: Changes of the somatotopic map within the S1 cortex may depend on CRPS pain and its recovery.