As per a recent study published in April issue of ‘PAIN- The journal of the International Association for the Study of Pain’, high-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex (M1) spaced at 3 weeks offers a persistent analgesic effect and encourage the clinical interest of this stimulation paradigm for refractory chronic pain treatment.

Repetitive transcranial magnetic stimulation (rTMS) has been proved to be safe and well tolerated treatment for patients with central neuropathic pain, although its efficacy is still unclear.

In this placebo-controlled randomized crossover study, the patients suffering from medically refractory chronic central neuropathic pain were involved in 2 randomized phases (i.e active and sham), with a wash-out period of 8 weeks. Every phase comprised of 4 consecutive rTMS sessions along with a last evaluation session. Each of these sessions were performed at an interval of 3 weeks.

A neuro-navigated robotic system was used to deliver high-frequency (20 Hz) rTMS over the M1 contralateral to the patient's pain. The pain relief in percentage  (%R) from baseline was considered as a primary outcome. The visual analogue scale (VAS) score, Neuropathic Pain Symptom Inventory, analgesic drug intake, and quality of life (EQ-5D) were all considered under secondary outcomes. Thirty-six patients reported no adverse effects throughout the study.

Analgesic effect (%R) was considerably higher in the active phase as compared to the sham phase. Same case was observed in the secondary outcome VAS. There was no difference observed regarding quality of life or analgesic drug intake. All in all, 17 patients were recognized as responders. There was no significant interaction found between clinical and technical factors and the analgesic response.