Comparison of the effects of transcranial direct current stimulation and transcutaneous tibial nerve stimulation on the urgency and frequency of women with overactive bladder syndrome: study protocol of a randomized clinical trial

Abstract Background Overactive bladder syndrome is common, with a prevalence of 12–17% among adults. Posterior tibial nerve stimulation is the primary nonpharmacological and conservative treatment for overactive bladder syndrome. While several human brain imaging studies have shown the involvement of supraspinal centers in bladder control, a literature review has found that no research has specifically investigated cortical stimulation through transcranial direct current stimulation as a treatment for overactive bladder syndrome in women. Therefore, this study aims to assess the potential benefits of transcranial direct current stimulation (tDCS) and compare them with the effects of posterior tibial nerve stimulation on overactive bladder syndrome. Methods/design The random allocation method will be used to divide the participants into two groups. Group 1 (n = 19) will undergo pelvic floor muscle training and transcutaneous tibial nerve stimulation. Group 2 (n = 19) will undergo pelvic floor muscle training and transcranial direct current stimulation. The transcranial direct current stimulation for group 2 will consist of 12 sessions occurring thrice a week, each lasting for 20 min. Anodal tDCS will be administered to FPz targeting the medial prefrontal cortex (mPFC) for 12 sessions, with the cathode electrode positioned between Oz and inion at an intensity of 2 mA for 20 min. Discussion It is believed that utilizing an approach involving non-invasive electrical stimulation of the cortex could lead to a more efficient treatment for individuals with overactive bladder. Additionally, it is theorized that combining the effects of tDCS and pelvic floor muscle training could present an innovative technique for alleviating the negative impacts of overactive bladder syndrome. Ultimately, this new method could provide help for patients who have not responded to conventional therapy. Trial registration Iranian Registry of Clinical Trials (IRCT) ID: IRCT20090301001722N26, registration date: May 17, 2023. https://en.irct.ir/ .