Management of neuropathic central pain by non-invasive brain stimulation and mirror therapy

Abstract

Central neuropathic pain is common among neurological patients. Drug therapy has high pharmacoresistance and some GABAergic agents can be detrimental to the recovery process. Alternative therapies include neuromodulation techniques, such as repetitive transcranial magnetic stimulation (rTMS) and motor imagery techniques with mirror therapy. The objective of this study was to evaluate their effectiveness in clinical practice on central neuropathic pain. Thirty-two patients followed in the Physical Medicine and Rehabilitation department of Rangueil University Hospital were included. Subjects with central neurological disease (from stroke, spinal cord injury, etc.) failed drug therapy with DN4 ≥ 4. They received a first session of rTMS of 20 minutes (10 Hz frequency and intensity of 90% of the motor threshold) over the controlateral pain motor cortex then daily rTMS sessions were conducted over 5 days with motor imagery exercises and mirror therapy twice daily. Effectiveness was assessed by changes in the BPI score at 2 days, 1 month, 3 months and 6 months. At 2 days (31 patients), scores of BPI3, 5, 9 and BPI severity decreased significantly (of respectively 12.6%, P = 0.001; 10.4%, P = 0.025; 28.2%, P = 0.000 and 8.6%, P = 0.001). At 1 month (20 patients), scores of BPI 3, 5, 6, 9 and BPI severity decreased significantly (of respectively 20,8%, P = 0.011; 26.1%, P = 0.005; 26%, P = 0.045; 32.5%, P = 0.009 et 24.5%, P = 0.022). At 2 days, pain ≤ 2 years was associated with better response to treatment (responders: lower BPI severity score ≥ 2 points) (Chi2 test, P = 0.04). The positive response found at 2 days is also correlated to a positive response at 1 month (Chi2 test, P = 0.011). The preliminary results of this study show a significant decrease in pain at 48 hours and 1 month intervals. A positive response at 48 hours indicates a good predictor of response to therapeutic treatment.