Background:There is currently few information regarding rehabilitation in patients with systemic autoimmune myopathies (SAMs). Transcranial direct current stimulation (tDCS) has shown promising results for the motor performance of healthy individuals as for patients with, e.g., post-stroke hemiparetic limbs.Objectives:The present study was aimed to assessing the safety and efficiency of tDCS in patients with SAMs.Methods:This study is a prospective, randomized, sham controlled, double blind, and clinical trial with ethical approval. Eighteen adult patients with dermatomyositis, polymyositis, antisynthetase syndrome or immune-mediated necrotizing myopathies in remission or with minimal disease activity were enrolled from 2018 to 2019. Patients were allocated randomly in two groups to receive sham or active tDCS with 2mA amplitude submitted for 20 minutes for three consecutive days. The 5x7cm sponge-electrodes were positioned with the anode over the left (C1) or right (C2) - contralateral to the dominant limb, whereas the cathode over the FP2 or FP3, respectively (10-10 EEG electrodes placement). The groups were evaluated in four moments: pre-stimulation, and 30 minutes, 3 weeks and 8 weeks post-tDCS. They were evaluated in the different moments with International Myositis Assessment and Clinical Studies Group set scores, Short-Form health survey (SF-36), state-trait anxiety inventory (STAI), Beck depression inventory (BDI), timed up-and-go test (TUG), time-stands test (TST), isokinetic extension and flexion testing of bilateral knee and elbow. A specific security questionnaire for tDCS was used after the active or sham stimulation in all patients.Results:The demographic data, kind of myositis, disease duration, and disease status (all with low disease activity) were comparable between both active and sham tDCS groups. After interventions, there was improvement of values of patient’s VAS (P=0.042) and serum levels of creatine phosphokinase (P=0.005), independent of the group. Moreover, in active tDCS group, the physical aspects of SF-36 in week 8 (P<0.001), mean and better TST at each evaluation (P<0.001), absolute peak tork (P<0.001) and peak tork adjusted for body weight values (P<0.001) of stimulated inferior limb extension also improved. No differences were observed in the STAI, BDI, or TUG in both groups. The patients’ adherence to the protocol was 100% and no adverse event was reported, including disease relapsing.Conclusion:This unprecedented study evidences the safety of tDCS, besides the potential efficiency in improving rehabilitation of tDCS in SAMs. More studies with a large samples and period of tDCS sessions are necessaries to corroborate with the present study.References:[1]Lundberg IE, et al. 2017 European league against rheumatism/ American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups. Arthritis Rheum. 2017;69:2271-82.[2]Tanaka S, et al. Single session of transcranial direct current stimulation transiently increases knee extensor force in patients with hemiparetic stroke. Neurorehabil Neural Repair. 2011;25:565-9.Acknowledgements:This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) 303.379/2018-9, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) 2019/11776-6, Faculdade de Medicina da USP/SP to SKS.Disclosure of Interests:None declared
