Motor control in complex regional pain syndrome: A kinematic analysis

This study evaluated movement velocity, frequency, and amplitude, as well as the number of arrests in three different subject groups, by kinematic analysis of repetitive movements during a finger tapping (FT) task. The most affected hands of 80 patients with complex regional pain syndrome (CRPS) were compared with the most affected hands of 60 patients with Parkinson disease (PD) as well as the nondominant hands of 75 healthy control (HC) subjects. Fifteen seconds of FT with thumb and index finger were recorded by a 60-Hz camera, which allowed the whole movement cycle to be evaluated and the above mentioned movement parameters to be calculated. We found that CRPS patients were slower and tapped with more arrests than the two other groups. Moreover, in comparison with the hands of the HC subjects, the unaffected hands of the CRPS patients were also impaired in these domains. Impairment was not related to pain. Dystonic CRPS patients performed less well than CRPS patients without dystonia. In conclusion, this study shows that voluntary motor control in CRPS patients is impaired at both the affected as well as the unaffected side, pointing at involvement of central motor processing circuits. (C) 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.