Pilot study of feasibility and effect of anodal transcutaneous spinal direct current stimulation on chronic neuropathic pain after spinal cord injury

Study design A single-blind crossover study. Objectives This study aimed to evaluate neuropathic pain in persons with spinal cord injury (SCI) after the application of transcutaneous spinal direct current stimulation (tsDCS). Setting Outpatient Clinic of the Rehabilitation Department, Seoul National University Hospital. Methods The effect of single sessions of both anodal and sham tsDCS (2 mA, 20 min) on chronic neuropathic pain in ten volunteers with complete motor cervical SCI was assessed. The active electrode was placed over the spinal process of the tenth thoracic vertebra and the reference electrode, at the top of the head. Pre- to post-tsDCS intervention changes in pain intensity (numeric rating scale, NRS), patient global assessment, and present pain intensity (PPI) were assessed before and after the tsDCS session (immediately post stimulation, and at 1 and 2 h post stimulation). Results All participants underwent the stimulation procedure without dropout. Our results showed no significant pre- to post-treatment difference in pain intensity between the active and sham tsDCS groups. Only in the sham tsDCS stimulation, NRS and PPI scores were reduced after the stimulation session. Furthermore, in the mixed effect model analysis, the response in the second period appeared to be more favorable. Conclusion The results suggest that a single session of anodal tsDCS with the montage used in this study is feasible but does not have a significant analgesic effect in individuals with chronic cervical SCI.