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Cortical neurostimulation in chronic pain: between anecdote and evidence

Cortical neurostimulation based on the implantation of epidural electrodes on the precentral cortex has been used to treat pain with considerable success since the 1990s. The work carried out on patients, healthy subjects and animal models has established the most plausible mechanisms of this type. of treatment. The “non-invasive” versions of cortical stimulation (magnetic transcranial stimulation, or rTMS) were initially used to predict the subsequent efficacy of implantable systems, and thus improve patient selection, but their use has progressed in the last decade. until established as autonomous treatment procedures. Several clinical trials and meta-analyzes have produced data favorable to the clinical utility of non-invasive stimulation by rTMS or tDCS; however, its mechanisms of action have been less studied than those of epidural stimulation, and clinical publications are often of mediocre quality and are subject to multiple biases. Despite these uncertainties, a certain percentage of patients with drug-resistant neuropathic pain respond favorably to transcranial stimulation, reduce their drug intake with it and wish to continue this mode of long-term treatment. This favorable result also poses problems, since the effect of stimulation decreases over time and needs the repetition of the sessions. Patients who respond to transcranial neurostimulation face the dilemma of accepting a surgical implant (not always possible) or continuing with iterative visits to the hospital for years, which poses logistical problems and availability of pain centers. The maintenance of the effect is therefore a limiting factor in the long-term use of these techniques. In the talk we will present the potential mechanisms that underlie the anti-allergic efficacy of rTMS and tDCS, and the current strategies to maintain their favorable effects in the long term. Among these, we will devote special attention to the combination of different cortical targets, to slow-pace stimulation and increasing intervals, and to ambulatory stimulation systems that allow semi-autonomous stimulation at home, controlled via the Internet.

Luis García-Larrea

  • Luis Garcia-Larrea (Madrid, 1956) obtained his MD and PhD degrees and the specialisation in Clinical Neurophysiology from the University of Barcelona (Spain).
  • He is currently Research Director at the INSERM (National Agency for Medical Research, France), Head of the Inserm / University research Lab “Central Integration of Pain in Humans” (NeuroPain) at the Centre for Neuroscience of Lyon, and member of the Pain Center at the Lyon Neurological Hospital.
  • His main research interests are the cortical processing of somatic sensations, the diagnosis and prediction of neuropathic pain, and its therapy using cortical neurostimulation. He is author of more than 200 scientific publications and 50 didactic papers on these topics, and Editor of the Book “Pain in the Conscious Brain” (IASP–Wolters-Kluver 2016). He served as President of the French (2008-10) and European (2010-2015) Societies of Clinical Neurophysiology, as Deputy Director of the Human Biology Department of Lyon Claude Bernard University (2013-2018), and is currently Editor-in-Chief of The European Journal of Pain (2016 – ).
  • He serves as member of the European Task Forces for the Assessment of neuropathic pain and neurostimulation techniques (European Federation of Neurology – EFNS), and has received awards from the Institut de France (Neuroscience Prize 2009; Pain research prize 2015), the French Pain Society (Translational Research Award 2013) and the IASP (Ronald Melzack Award 2012).

Luis García-Larrea

  • Luis Garcia-Larrea (Madrid, 1956) obtained his MD and PhD degrees and the specialisation in Clinical Neurophysiology from the University of Barcelona (Spain).
  • He is currently Research Director at the INSERM (National Agency for Medical Research, France), Head of the Inserm / University research Lab “Central Integration of Pain in Humans” (NeuroPain) at the Centre for Neuroscience of Lyon, and member of the Pain Center at the Lyon Neurological Hospital.
  • His main research interests are the cortical processing of somatic sensations, the diagnosis and prediction of neuropathic pain, and its therapy using cortical neurostimulation. He is author of more than 200 scientific publications and 50 didactic papers on these topics, and Editor of the Book “Pain in the Conscious Brain” (IASP–Wolters-Kluver 2016). He served as President of the French (2008-10) and European (2010-2015) Societies of Clinical Neurophysiology, as Deputy Director of the Human Biology Department of Lyon Claude Bernard University (2013-2018), and is currently Editor-in-Chief of The European Journal of Pain (2016 – ).
  • He serves as member of the European Task Forces for the Assessment of neuropathic pain and neurostimulation techniques (European Federation of Neurology – EFNS), and has received awards from the Institut de France (Neuroscience Prize 2009; Pain research prize 2015), the French Pain Society (Translational Research Award 2013) and the IASP (Ronald Melzack Award 2012).

Cortical neurostimulation in chronic pain: between anecdote and evidence

Cortical neurostimulation based on the implantation of epidural electrodes on the precentral cortex has been used to treat pain with considerable success since the 1990s. The work carried out on patients, healthy subjects and animal models has established the most plausible mechanisms of this type. of treatment. The “non-invasive” versions of cortical stimulation (magnetic transcranial stimulation, or rTMS) were initially used to predict the subsequent efficacy of implantable systems, and thus improve patient selection, but their use has progressed in the last decade. until established as autonomous treatment procedures. Several clinical trials and meta-analyzes have produced data favorable to the clinical utility of non-invasive stimulation by rTMS or tDCS; however, its mechanisms of action have been less studied than those of epidural stimulation, and clinical publications are often of mediocre quality and are subject to multiple biases. Despite these uncertainties, a certain percentage of patients with drug-resistant neuropathic pain respond favorably to transcranial stimulation, reduce their drug intake with it and wish to continue this mode of long-term treatment. This favorable result also poses problems, since the effect of stimulation decreases over time and needs the repetition of the sessions. Patients who respond to transcranial neurostimulation face the dilemma of accepting a surgical implant (not always possible) or continuing with iterative visits to the hospital for years, which poses logistical problems and availability of pain centers. The maintenance of the effect is therefore a limiting factor in the long-term use of these techniques. In the talk we will present the potential mechanisms that underlie the anti-allergic efficacy of rTMS and tDCS, and the current strategies to maintain their favorable effects in the long term. Among these, we will devote special attention to the combination of different cortical targets, to slow-pace stimulation and increasing intervals, and to ambulatory stimulation systems that allow semi-autonomous stimulation at home, controlled via the Internet.