neuropathic pain intervention with tdcs in brazilian military personnel (neubrain trial)

Conditions: Neuropathic Pain; Sleep Quality; Transcranial Direct Current Stimulation

Summary: this project protocol investigates the efficacy of transcranial direct current stimulation (tdcs) in treating neuropathic pain and improving sleep quality among brazilian military personnel. given the high prevalence of chronic pain and sleep disturbances in this population, and the limitations of current pharmacological treatments, our randomized, triple-blinded, sham-controlled trial explores the potential of tdcs as a non-invasive therapeutic intervention. the results of this study could have a significant impact on improving the well-being and performance of military personnel, while also reducing healthcare costs associated with long-term medication use.

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.

Eligibility criteria:
inclusion criteria: * military personnel (active and veterans) with chronic pain due to central or peripheral neuropathy and poor sleep quality; * age over 18 years old; * defined chronic nep according to current guidelines (icd-10 codes or dn-4); * pain with an average intensity score above 40/100 mm on a visual analogue scale (vas); * medication stability (chronic pain, depression, anxiety, sleep) for at least six weeks; * patients with bad sleep quality identified by the pittsburgh sleep quality index (psqi) of 5 or more who do not improve under conventional treatment. exclusion criteria: * general contraindications for tdcs: past head trauma, current epilepsy, intracranial ferromagnetic components, pacemaker, implanted microprocessors (i.e., cochlear implants); * pregnancy; * known major psychiatric disorders (as assessed by the dsm-5, e.g., psychosis), history of substance abuse, or work litigation issues; * history of chronic refractory migraines; * non-treated moderate to severe sleep apnea defined as apnea/hypopnea index greater than 15 events per hour in baseline polysomnography; * skin conditions such as psoriasis or eczema that involve the scalp (thair et al, 2017); * cancer-related pain; * bmi \>35, due to increased reports of pain associated with increased bmi (basem, et al., 2021; stokes et al., 2020); * patients who do not sign informed consent or do not want to participate in the study.

Keywords: transcranial current stimulation neuropathic pain sleep