Objectives: We tested whether repetitive magnetic stimulation (rMS) induces an afferent input to the spinocerebral tract in patients with complex regional pain syndrome (CRPS).
Methods: Cortical and spinal motor evoked potentials (cMEP and sMEP), as well as the contra- and ipsilateral silent period (cCSP and iCSP), were recorded in patients with CRPS type I before and after conditioning rMS, applied at cervical nerve roots innervating affected muscles. Patients were compared with a group of healthy subjects.
Results: In the group of patients we found that cMEP amplitudes were always significantly smaller for both hemispheres. In the group of healthy subjects we found a significant prolongation of the cCSP and iCSP after rMS. This was absent in patients. SMEP were always unchanged in both groups.
Discussion: This led us to the explanation that the afferent input to the motor cortical system in CRPS patients is less effective than in healthy subjects.