Transcranial direct current stimulation in obsessive-compulsive disorder: emerging clinical evidence and considerations for optimal montage of electrodes.

BACKGROUND: Neuromodulation techniques for obsessive-compulsive disorder (OCD) treatment have expanded with greater understanding of the brain circuits involved. Transcranial direct current stimulation (tDCS) might be a potential new treatment for OCD, although the optimal montage is unclear. OBJECTIVE: To perform a systematic review on meta-analyses of repetitive transcranianal magnetic stimulation (rTMS) and deep brain stimulation (DBS) trials for OCD, aiming to identify brain stimulation targets for future tDCS trials and to support the empirical evidence with computer head modeling analysis. METHODS: Systematic reviews of rTMS and DBS trials on OCD in Pubmed/MEDLINE were searched. For the tDCS computational analysis, we employed head models with the goal of optimally targeting current delivery to structures of interest. RESULTS: Only three references matched our eligibility criteria. We simulated four different electrodes montages and analyzed current direction and intensity. CONCLUSION: Although DBS, rTMS and tDCS are not directly comparable and our theoretical model, based on DBS and rTMS targets, needs empirical validation, we found that the tDCS montage with the cathode over the pre-supplementary motor area and extra-cephalic anode seems to activate most of the areas related to OCD.

Evolutionary coil design for maximally uniform magnetic fields.

Magnetic fields and their applications in medicine and biology are an active area of research in recent years. Some of these applications include chronic wound healing, electrical stimulation of cardiac tissue and medical imaging among others. The effectiveness of these applications strongly relies on the uniformity of the field, a feature closely related to the arrangement of the coils that generates it. In this paper, genetic algorithms are used to create appropriate arrangements of coils in order to generate a field with a wide volume of uniformity. Results show that the proposed methodology is an effective tool for designing coil arrangements capable of generating magnetic field within an arbitrary volume of interest in which field uniformity is higher than in designs using a traditional approach.