TMS motor cortical brain mapping in patients with complex regional pain syndrome type I

Objective The motor cortical representation in patients with complex regional pain syndrome type I (CRPS I) was determined under the assumption that the motor cortex undergoes representational adaptations in the course of CRPS. Methods A total of 14 patients with CRPS I and a group of healthy subjects without any known neurological symptoms participated in the study. The motor cortical representation, i.e. the size of representation (cm2), motor-evoked potentials (MEP), the calculated volume (cm2 mV), and the center of gravity (CoG) were measured by transcranial magnetic stimulation. Recordings were made of the long extensor muscles of the forearm of the affected and unaffected hand. Results Analyses of the results revealed a significant asymmetry between the two hemispheres: the motor cortical representation corresponding to the unaffected hand was significantly larger. While the CoG data did not differ statistically between the two hemispheres, the CoG coordinates corresponding to the affected hand indicated a larger variability. Conclusions The presence of pain and other CRPS symptoms may induce lasting changes in motor cortical plasticity, as it also does in the sensory cortex. Significance This could be of importance in rehabilitative strategies for the sensory motor system in CRPS I patients.