Comparison of the analgesic effects of two methods of repetitive magnetic transcranial stimulation: A randomized double blind sham controlled study in patients with central neuropathic pain

Ambroise Paré hospital France, Henri Mondor hospital France, Oslo University Norwey

Neuropathy is common in the diabetic population, affecting approximately 50% of patients with long-lasting diseases. The most common type is symmetric distal sensorimotor polyneuropathy, in which pain is a dominant symptom.

Although painful neuropathy responds to antidepressants, anticonvulsants and opioid agonists, these drugs are often ineffective or can induce severe adverse effects. Hence, to manage this condition effectively, we need to seek other safe and effective therapeutic options.

Invasive neurostimulation techniques are already used successfully to treat drug-resistant neuropathic pain, including brain stimulation and epidural motor cortex stimulation.

rTMS of the motor cortex is an increasingly established analgesic technique for the treatment of neuropathic pain. However, its efficacy is generally modest. One reason may be the that conventional rTMS targets only superficial and small cortical regions of the human brain. A newer cooled coil, the Hesed (H) coils, now allows deep and larger surface of stimulation and has been suggested to have analgesic effects in a small pilot trial in diabetic painful polyneuropathy. Based on its deeper mechanism of action and larger surface of stimulation, we hypothesize that this technique will be more effective than rTMS in patients with central pain, a highly unmet medical need. The primary objective of the present study will be to compare the efficacy of H coil, conventional rTMS and sham stimulation of the primary motor cortex in patients central neuropathic pain. Major secondary objectives will be to directly compare the analgesic efficacy of H coil versus conventional rTMS, and compare the efficacy of both techniques in patients with lower limb pain and those with upper limb pain/face. This will be a randomized tricentric sham controlled study.

Contact information: Nadine ATTAL,MD PhD – nadine.attal@aphp.fr