Using Transcranial Direct Current Stimulation (tDCS) to Augment a Behavioral Intervention for Vaginismus

Abstract

Background: Lifelong vaginismus is a condition in which a woman has pelvic muscle spasm and pain that limits or precludes coitus or insertion of objects such as a tampon or speculum, affecting between 6–17% of women. Agreed-upon treatments do not exist, though vaginal trainers are often used b to treat women with this condition. Transcranial direct current stimulation (tDCS) is a type of neuromodulation used to treat muscle dystonia, spasm, and pain. Aims: The aims of the study were to compare the effect of using sham and active tDCS on 1) pelvic floor muscle sEMG and 2) secondary measures of pain, muscle tone, vaginal trainer (VT) accommodation and questionnaires, including the Female Sexual Function Index (FSFI), Pain Catastrophizing Scale (PCS), and Beck Depression Inventory (BDI)). Methods & Study design: The study design was a double-blinded, mixed model with participants randomized to sham or active tDCS groups, both receiving the same VT behavioral intervention three times a week for four weeks. Comparisons between and within subjects were made before and after treatment, over time and from baseline to a one-month follow up depending on the study measure. Results: Seventeen women completed the study. For the primary measure of pelvic sEMG, within the active tDCS group, there was a significant improvement in the ability to match a square wave with 10-second isometric contractions. There were no other significant findings between or within groups for any other EMG findings. There was a significant main effect with pain and muscle tone significantly improving in active versus sham tDCS. Both groups improved significantly and equally in terms of VT accommodation and self-report measures of sexual function, pain, and affect. Discussion/Conclusion: Active tDCS appears to have augmented VT by improving muscle control by reducing muscle tension and pain. The behavioral VT treatment protocol also proved to be effective as a stand-alone treatment in regards to pain, muscle tension, VT accommodation, and outcomes questionnaires.