Efficacy of Transcranial Direct-Current Stimulation (tDCS) for Provoked Vestibulodynia : a Triple Blind Randomized Controlled Trial

Provoked vestibulodynia (PVD) is the most common form of vulvodynia and despite its high prevalence and important sexual, conjugal and psychological deleterious repercussions, effective evidence-based interventions remain limited. For a high proportion of women, significant pain persists despite the currently available treatments. Transcranial direct-current stimulation (tDCS) was shown to be effective in various chronic pain conditions. So far, only one case report study has shown significant pain reduction in women with vulvodynia. The main goal of this randomized controlled trial is to evaluate the efficacy of tDCS in women with PVD compared to sham tDCS. Forty women diagnosed with PVD, by a gynecologist following a standardized protocol will be randomized to either active or sham tDCS for ten 20 minute sessions of 2 mA stimulation over a 2-week period. Outcome measures will be collected at baseline, after treatment and at 3-month follow-up. The primary outcome is pain during intercourse assessed with a numerical rating scale (NRS). Secondary measurements focus on sexual function, vestibular pain sensitivity, psychological distress, treatment satisfaction and Patient Global Impression of Change (PGIC). The investigators expect that active tDCS treatment will significantly reduce pain during intercourse (post-treatment and 3-month follow-up compared to pre-treatment assessment). This trial will provide important information for determining the efficacy of a novel and promising intervention for women with PVD.

Inclusion Criteria:

1. Experience moderate to severe pain in at least 90% of attempted sexual intercourse;
2. Experience moderate to severe pain during cotton swab test, in one or more regions of the vestibule (minimum of 5/10 on a subjective numeric scale of pain intensity);
3. Pain limited to the vestibule during vaginal intercourse and during activities exerting pressure on the vestibule (tampon insertion, tight jeans or pants, cycling, horseback riding);
4. Presence of PVD for at least 6 months and diagnosed according to the standardized gynecological examination protocol by one of our staff gynecologists;
5. Have a stable sexual partner with regular sexual activity including penetration.

Exclusion Criteria:

1. Other pelvic pathology associated with pelvic pain (e.g., deep dyspareunia);
2. Chronic pain conditions (e.g. fibromyalgia, low back pain, chronic migraines);
3. Use of medication that can influence the perception of pain (eg analgesic, opioids, antiepileptic, muscle relaxant);
4. Pregnancy for less than one year and breastfeeding;
5. Anterior vulvar or vaginal surgery;
6. Refusal to refrain from other treatments one month prior to first treatment study until the last 3-month follow-up assessment;
7. Important urogynecologic symptoms (urinary or anal incontinence, urinary urgency, pelvic organ prolapse, active urinary tract or vaginal infection or earlier in the last 3 months, etc.);
8. Contraindications to tDCS (e.g. metallic implant in or near the skull, history of epilepsy, pacemaker);
9. Previously received tDCS treatment.