Neuropathic Pain Intervention With tDCS in Brazilian Military Personnel (NeuBRAIN Trial)

The intervention will be carried out into two-weeks daily consecutive sessions of 20 minutes each, with 1 session per day, and a weekend interval. Direct current stimulation will be administered through an electrical stimulator model MicroEstim Genius (NKL), Brusque, Brazil. During the session, the participants will be awake and seated in a comfortable seat. The environment will be air-conditioned, free of visual and auditory stimuli. The sessions will be conducted by a trained health professional. The groups will receive single-phase direct current with an intensity of 2 mA up, according to data presented by Pacheco-Barrios et al. (2021). Electrodes with a size of 35cm² (5 x 7 centimeters) will be used. Electrodes will be placed on the scalp, fixed with elastic bands, and immersed in 10 to 12 mL of saline solution. The electrode montage will be performed for one of two possible targets: anodal stimulation over DLPFC or anodal stimulation over M1, and also sham in both targets according to the participants' designations after randomization to one of the three groups. The device displays will be identical across active and sham groups, and to ensure blinding, an active current will be applied for 30 seconds at the beginning and end of the sham stimulation to mimic the sensation of the current ramp experienced in active stimulation. Stimulations of less than 3 minutes of tDCS do not induce cortical excitability effects, according to Nitsche and Paulus (2000), being safely inactive for the expected results.