Exposition sonore et répercussions auditives au cours de la stimulation magnétique transcrânienne répétitive : données récentes et revue de la littérature

Multi-objective optimization method for coil current waveform of transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) has been proved to be effective in the treatment of many kinds of mental diseases. However, the clicking noise produced by the pulse current with large amplitude and short duration in the TMS coil may damage the hearing of patients. The heat produced by the high-frequency pulse current in the coil also reduces the efficiency of TMS equipment. A multi-objective waveform optimization method to improve heat and noise problems at the same time is presented. By analyzing the current waveforms of TMS, the relationship between the current and the vibration energy/Joule heating is established. Taking the Joule heating and the vibration energy as the optimization objectives, exceeding the same amount of neuronal membrane potential as the limiting condition, the Pareto fronts of different current models are obtained by applying the multi-objective particle swarm optimization algorithm (MOPSO). Therefore, the corresponding current waveforms are inversely deduced. A ringing suppression cTMS (RS-cTMS) proof-of-principle experimental platform is constructed. The feasibility of the proposed method is validated through experiments. The results show that the optimized current waveforms can greatly reduce the vibration and heating of the coil compared with the conventional full-sine, recified sine and half-sine waveforms, thus reducing the pulse noise and prolonging the using time of the equipment. The optimized diversified waveforms also provide a reference for the diversity of TMS.

Evidence-based guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS): An update (2014-2018)

A group of European experts reappraised the guidelines on the therapeutic efficacy of repetitive transcranial magnetic stimulation (rTMS) previously published in 2014 [Lefaucheur et al., Clin Neurophysiol 2014;125:2150-206]. These updated recommendations take into account all rTMS publications, including data prior to 2014, as well as currently reviewed literature until the end of 2018. Level A evidence (definite efficacy) was reached for: high-frequency (HF) rTMS of the primary motor cortex (M1) contralateral to the painful side for neuropathic pain; HF-rTMS of the left dorsolateral prefrontal cortex (DLPFC) using a figure-of-8 or a H1-coil for depression; low-frequency (LF) rTMS of contralesional M1 for hand motor recovery in the post-acute stage of stroke. Level B evidence (probable efficacy) was reached for: HF-rTMS of the left M1 or DLPFC for improving quality of life or pain, respectively, in fibromyalgia; HF-rTMS of bilateral M1 regions or the left DLPFC for improving motor impairment or depression, respectively, in Parkinson's disease; HF-rTMS of ipsilesional M1 for promoting motor recovery at the post-acute stage of stroke; intermittent theta burst stimulation targeted to the leg motor cortex for lower limb spasticity in multiple sclerosis; HF-rTMS of the right DLPFC in posttraumatic stress disorder; LF-rTMS of the right inferior frontal gyrus in chronic post-stroke non-fluent aphasia; LF-rTMS of the right DLPFC in depression; and bihemispheric stimulation of the DLPFC combining right-sided LF-rTMS (or continuous theta burst stimulation) and left-sided HF-rTMS (or intermittent theta burst stimulation) in depression. Level A/B evidence is not reached concerning efficacy of rTMS in any other condition. The current recommendations are based on the differences reached in therapeutic efficacy of real vs. sham rTMS protocols, replicated in a sufficient number of independent studies. This does not mean that the benefit produced by rTMS inevitably reaches a level of clinical relevance.