Analgesic Effect of Non Invasive Stimulation : Comparison of rTMS and tDCS Efficacy

Non-invasive Cortical Stimulation for Pharmacoresistant Neuropathic Pain: rTMS Versus tDCS

The aim of this study is to compare analgesic efficacy of two non invasive techniques based on motor cortex stimulation in neuropathic pain patients. High frequency repetitive transcranial magnetic stimulation (HF-rTMS) of primary motor cortex has been demonstrated to induce an analgesic effect significantly different from placebo; this effect is clinically useful if rTMS sessions are applied daily during five consecutive days. Transcranial direct current stimulation (tDCS) is a new approach of non invasive cortical stimulation but its efficacy in neuropathic pain has been not yet established. The investigators propose to compare the analgesic effect of 5 tDCS sessions applied daily to a similar protocol using HF-rTMS. In parallel to the clinical therapeutic evaluation, functional-MRI will be performed before and after the five sessions of rTMS and tDCS, in order to reveal the potential plasticity induced within motor somatotopic map of the primary motor cortex.

Inclusion Criteria:

• patients aged from 18 to 80 years, male or female, fully informed and having given their written consent
• pharmacoresistant neuropathic pain during at least one year, without any change of the pharmacological treatment since at least one month

Exclusion Criteria:

• drug addiction, headache, epilepsy history
• ferromagnetic intracranial device
• implanted stimulator
• absence of contraceptive method for women of childbearing age