The Safety and Feasibility of Transcranial Direct Current Stimulation Combined with Conservative Treatment for Patients with Cervicogenic Headaches: A Double-Blinded Randomized Control Study Protocol

Abstract Background Cervicogenic headaches (CGH) are common following concussion and whiplash injuries and significantly reduce patient quality of life. CGH is often associated with neck, jaw and/or facial pain and reduced neck mobility. Conservative therapy and injection-based therapies are cornerstones of treatment for CGH but have shown limited efficacy. Transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) has shown promise in treating other chronic pain and headache conditions. The primary aim of this trial is to evaluate the feasibility and safety of tDCS when combined with conservative therapy for the treatment of CGH. The study will evaluate retention and dropout rates, adherence to the protocol and adverse events. Exploratory aims will investigate the association of CGH and various health outcomes, inclusive of pain intensity, headache frequency and duration, neck mobility, quality of life, pain sensitivity, and medication usage. Methods Forty adults (aged 18–65), blinded to treatment arm, will be randomized into one of two groups: active tDCS with conservative therapy or sham tDCS with conservative therapy. tDCS will be applied over M1 by a trained research assistant three times per week for 6 weeks. Conservative therapy will be provided immediately post-tDCS. The primary outcomes of this trial will be the feasibility and safety of this intervention. Feasibility will be defined as greater than 30% recruitment, greater than 70% protocol adherence, and greater than 70% retention rate. Safety will be defined as no severe adverse events and less than 30% increase in adverse effects. Secondary exploratory outcomes will be assessed using the following: numeric pain rating scale (NPRS), headache impact test-6 (HIT-6), rivermead PPCS questionnaire (RPQ), cranio-cervical flexion test (CCFT), cervical extensor endurance test (CEET), cervical flexor endurance test (CFET), dynamometry neck-strength assessment (DNSA), the European quality of life five dimension (EQ-5D), patient reported outcomes measurement information system (PROMIS) pain interference scale, pain catastrophizing scale (PCS), and section A - quantitative analgesics questionnaire (QAQ-A). Discussion This pilot study will be the first to evaluate the use of tDCS combined with conservative therapy for the treatment of cervicogenic headaches. Trial Registration: ClinicalTrials.gov - NCT05582616 (registered October 4th, 2022) https://clinicaltrials.gov/ct2/show/NCT05582616