Efficacy of Transcranial Direct Current Stimulation for Severe Primary Dysmenorrhea

Primary Dysmenorrhea (PDM), defined as menstrual pain without discernable organic causes, is inexorably common in adolescent women, about 40-90% of women may suffer from it, and 20% of them can be severe in the context of being refractory to medication, daily function impairment, and having pain of severe degree. Novel therapeutic method is in need for pain alleviation for this particular phenotype. We have previously reported that PDM females may engage motor-cortex based descending pain modulation system in our resting-state functional Magnetic Resonance Imaging (rs-fMRI) and thermal pain-activation fMRI studies. Based on the reported analgesic efficacy of transcranial Direct Current Stimulation (tDCS) on the motor cortex for various experimental painful conditions and clinical pain disorders, we reason that tDCS can be effective for the severe and medication-refractory PDM patients. This study aim to investigate the analgesic efficacy of tDCS in severe PDMs and to elucidate the dynamic brain neuroplasticity in the context of functional connectivity (FC) of pain matrix after tDCS intervention. We will recruit 30 severe PDMs and randomly allocate them to either real or sham group in a triple-blind manner. rs-fMRI for functional connectivity analysis will be performed before and after the tDCS intervention. The imaging data will be correlated with behavioral and psychological measurements. This is the first study in the literature investigating the tDCS efficacy for severe PDM. The result can promise a new possibility for clinical application.