Relevance and safety of non-invasive cerebral neuromodulation in patients with systemic autoimmune myopathies: double-blind, randomized, sham-controlled study

Abstract

Systemic autoimmune myopathies (SAMs) are a heterogeneous group of rare rheumatic diseases characterized clinically by progressive, symmetrical and predominantly proximal muscle limb weakness. SAMs may also affect joints, lung, heart and gastrointestinal tract. Despite drug treatment and guidance on performing regular physical exercises, the high frequency of fatigue and chronic pain in these patients is remarkable. These factors, in turn, impair functional capacity and quality of life, generating a mechanism of vicious cycle between these parameters. Thus, it becomes relevant to establish therapeutic strategies that may result in a decrease and/or a break in this vicious cycle.Several studies have shown the efficacy of using transcranial non-invasive neuromodulation (e.g., transcranial electrical current stimulation - tDCS) in a several diseases to reduce fatigue, modulate and reduce pain, and consequent improvement of functional capacity and quality of life. However, to date, there are no studies evaluating the safety and benefit of tDCS in patients with stable MAS. In this context, our group initiated two studies, the preliminary results of which have shown that 3 sessions of the tDCS is safe, without leading to MAS relapses.The present project aims to perform a greater number of sessions of tDCS, associated to physical exercises, in patients with MAS and different disease activities. The effectiveness of the technique (local and diffuse pain, fatigue, overall functionality, mobility, balance, muscular strength, functional capacity and quality of life) will be evaluated. This combination of central and peripheral techniques may result in greater connectivity of the neural network, promoting additional effects on muscle excitability, thus contributing to decreased perceived pain and fatigue, resulting in greater muscle recruitment, improved strength, muscle function, mobility and balance. In summary, an improvement in functional capacity and quality of life in patients with MAS may indicate the use of these techniques for the clinical and rheumatologic practice. (AU)