An interventional study of transcranial direct current stimulation (tDCS) and Sham Transcranial Direct Current Stimulation in Chronic Pain and Endometriosis, sponsored by Hospital de Clinicas de Porto Alegre. Completed at 1 site in Brazil. Open to female participants aged 18 Years to 55 Years. Per ClinicalTrials.gov, last updated 2026-01-15.
Sponsored by Hospital de Clinicas de Porto Alegre · Not applicable, Interventional, and Treatment
The purpose of this study is to determine if transcranial direct current stimulation (tDCS) is effective in the treatment of chronic pelvic pain associated with endometriosis
2,930 studies on the registry are indexed under Chronic Pain; 701 are open to participants now.
This study's enrollment of 30 is below the median of 60 across 2,161 interventional studies indexed under Chronic Pain.
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tDCS will be applied in the head of the patients in 20 minute sessions, daily from Monday to Friday for 2 weeks (10 sessions total). The stimulation will be administered with a pair of surface electrodes, sponge coated, soaked in saline. A battery-powered constant current stimulator will be used for this purpose (tDCS device Soterix 1X1). The stimulation is performed by placing the anodal electrode in the primary motor cortex (M1) and the cathodal one in the contralateral supraorbital area, and it will use a 2 mA current.
Device: transcranial direct current stimulation (tDCS)
The sham tDCS consists of the same montage of the active tDCS, but the device is turned off 30 seconds after initiating stimulation (without letting the patient notice it). Rest of the montage is kept identical as the active one during the 20 minutes that the session lasts.
Device: Sham Transcranial Direct Current Stimulation
The stimulation will be administered with a pair of surface electrodes, sponge coated, soaked in saline. A battery-powered constant current stimulator will be used for this purpose (tDCS device Soterix 1X1). The stimulation is performed by placing the anodal electrode in the primary motor cortex (M1) and the cathodal one in the contralateral supraorbital area and it will use a 2 mA current.
Also known as: tDCS
The sham tDCS consists of the same montage of the active tDCS, but the device is turned off 30 seconds after initiating stimulation (without letting the patient notice it). Rest of the montage is kept identical as the active one during the 20 minutes that the session lasts.
Also known as: Sham tDCS
Change in worst daily pain assessed with the visual analogue scale.
Patients will be asked to write down their worst pain level (assessed by the Visual Analogue Scale, self-administered) in a paper diary with different scores: global pain, pain during menses, pain during sexual intercourse, pain during urination, pain during defecation. They will also be asked to daily write the analgesic drug intake. Total evaluations: 35 days.
Time frame: Once Daily. Start 7 days before treatment, everyday during treatment period and every day during follow-up period (total = 35 days)
Changes in motor cortex blood flow assessed by near infrared spectroscopy
Motor cortex blood flow will be assessed before the first session of tDCS (on Treatment day 1), after the end of treatment period (Day 15) and after the follow-up period (Day 29). Total = 3 evaluations.
Time frame: Treatment Day 1 (before receiving the 1st session of tDCS); Day 15 (at the end of treatment period) and Day 29 (at the end of follow-up period)
Change in Functional Pain Scale
The Functional Pain Scale will be assessed by the Brazilian Profile of Chronic Pain: Screen (B-PCP:S) once a week, as follows: on Treatment Day 1 (before the first session of tDCS, considered baseline), on Treatment Day 8, Day 15, Day 22, and Day 29. Total = 5 evaluations.
Time frame: Once a week - Treatment Day 1, Day 8, Day 15, Day 22, Day 29
Change in the temperature pain threshold
It will be assessed by the Quantitative Sensory Test (QST) in the dominant (right) forearm. The heat pain tolerance and pain threshold to the heat and the temperature defined as pain 6/10 by the participant. The temperature starts at 32°C, and it heat at a 1.0 °C/sec rate and cools down after a button is pressed or whenever it reaches the max temperature of 52°C. The participant will be asked to press the button at the first sensation of pain to determine the pain threshold; to press the button whenever she can not stand the heat anymore for the pain tolerance determination and, for last, to press the button at the temperature she fells pain equivalent to 6/10 in the numeric scale of pain. The pain threshold and the temperature of pain 6/10 will be determined by the arithmetic mean of 3 evaluations each. Total of 3 test days: Day 1 (before the first session of tDCS), after the end of the Treatment period (Day 15) and at the end of the follow-up period (Day 29).
Time frame: up to Day 29
Change in effect of the descendent modulator system of pain
It will be assessed by the Conditioned Pain Modulation test (CPM). A nociceptive tonic conditioning stimulus - immersion of the non-dominant hand in cold water (0°C for 1 minute) - will be applied concomitant to the progressive thermal stimulus in the dominant forearm as applied in the QST pattern until it reaches the 6/10 pain temperature previously determined by the participant. It will be tested in Treatment Day 1 (before the first session of tDCS - considered baseline), after the end of the Treatment period (Day 15) and at the end of the follow-up period (Day 29) - Total = 3 evaluation.
Time frame: up to Day 29
Change in serum biomarkers level: The brain derived neurotrophic factor (BDNF) and interleukins
A blood sample will be collected to measure BDNF and interleukins on Treatment Day 1 (right before the first tDCS session - considered baseline), after the end of the treatment period (day 15,) and after the end of the follow-up period (day 29). Total = 3 evaluations
Time frame: up to Day 29
Depressive symptoms level
Depression symptoms will be assessed by using the Beck II Inventory. It will be assessed before the first session of tDCS (on Treatment day 1), after the end of treatment period (Day 15) and after the follow-up period (Day 29). Total = 3 evaluations.
Time frame: Treatment Day 1 (before receiving the 1st session of tDCS); Day 15 (at the end of treatment period) and Day 29 (at the end of follow-up period)
Anxiety level
Anxiety level will be assessed by State-Trait Anxiety Inventory (STAI), adapted to Brazilian Portuguese Language. It will be assessed before the first session of tDCS (on Treatment day 1), after the end of treatment period (Day 15) and after the follow-up period (Day 29). Total = 3 evaluations.
Time frame: Treatment Day 1 (before receiving the 1st session of tDCS); Day 15 (at the end of treatment period) and Day 29 (at the end of follow-up period)
Psychiatric diseases
Psychiatric diseases will be evaluated by the Structured Clinical Interview for DSM-IV (SCID) in the patient screening. Total = 1 evaluation
Time frame: 1day on patient screening
Estradiol level
Estradiol blood level will be measured on treatment Day 1 (before receiving the 1st session of tDCS). Total = 1 evaluation
Time frame: Treatment Day 1 (before receiving the 1st session of tDCS)
Adverse Effects
At the end of each tDCS session, the incidence of any adverse effects - paresthesia, headache, dizziness, nausea, neck pain, burns, redness or pain in the scalp, insomnia, abrupt humor changes and lack of concentration - will be questioned to the participant. Total = 10 evaluations
Time frame: up to Day 29
Pain catastrophizing thoughts
The level of catastrophic thinking will be assessed by the Pain Catastrophizing Scale on Treatment Day 1 (before receiving the 1st session of tDCS), after the treatment period (Day 15) and at the end of the follow-up period (Day29). Total = 3 evaluations
Time frame: Treatment Day 1 (before receiving the 1st session of tDCS); Day 15 (at the end of treatment period) and Day 29 (at the end of follow-up period)
Demographic data and comorbidities
Demographic data and comorbidities will be asked in the baseline (before the first session of tDCS). Total = 1 evaluation.
Time frame: Baseline
Change in quality of life
Quality of life will be assessed by the WHOQOL (World Health Organization Quality of Life), in Treatment Day 1 (before the first session of tDCS - considered baseline) and after the treatment period (Day 15). Total = 2 evaluations
Time frame: Baseline and Day 15
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Hospital de Clinicas de Porto Alegre