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. It has been 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, it is plausible 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 experimental pain after tDCS intervention. Thirty severe PDMs will be recruited and randomly allocated to either real or sham group in a triple-blind manner. Experimental pain electrical stimulation will be performed before and after the tDCS intervention. The experimental pain-evoked magnetoencephamographic (MEG) data will be correlated with behavioral and psychological measurements. This is the first study in the literature investigating the tDCS efficacy for acute pain in severe PDM. The result can promise a new possibility for clinical application.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
31
The anode and cathode sponge electrode (51 cm2) will be placed over C3 and FP2 (10-20 system) respectively. 2 mA current will be applied continuously for 20 minutes.
The anode and cathode sponge electrode (51 cm2) will be placed over C3 and FP2 (10-20 system) respectively. 2 mA current will be applied for 30 seconds at the beginning.
Taipei Veterans General Hospital
Taipei, Taiwan
Visual Analog Scale (VAS)
pain scale; from 0 to 10; score 0: no pain, score 10: unbearable pain
Time frame: change from baseline (1st menstrual phase, before tDCS) at one month (2nd menstrual phase, with tDCS), change from baseline (1st menstrual phase, before tDCS) at two months (3rd menstrual phase)
Somatosensory evoked magnetic fields to experimental pain
Somatosensory evoked magnetic fields (SEFs) is a well established magnetoencephalographic (MEG) cortical response evoked by electric stimulation. SEFs to experimental pain stimulation using electrical stimulator applied on the skin over the trajectory of median nerve will be used to evaluate pain-evoked cortical response.
Time frame: change from baseline (before tDCS, before 2nd menstrual phase) at one week (after tDCS completion), change from baseline (before tDCS, before 2nd menstrual phase) at four weeks (before the 3rd menstrual phase)
Quantitative sensory testing (QST)
To assess the threshold of thermal sensation (cold, cold-pain, heat, heat-pain; from 0 to 50 centigrade temperature), according to the established protocol of an ascending limit approach for heat pain and a descending limit approach for cold pain.
Time frame: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at four weeks (before the 3rd menstrual phase), change from baseline (before tDCS) at five weeks (after the 3rd menstrual phase)
Spielberger State-Trait Anxiety Inventory (STAI)
To assess anxious symptoms; from 20 to 80; score 20: not anxious, score 80: extremely anxious
Time frame: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at four weeks (before the 3rd menstrual phase), change from baseline (before tDCS) at five weeks (after the 3rd menstrual phase)
Beck Anxiety Inventory (BAI)
To assess anxious symptoms; from 0 to 63; score 0: not anxious, score 63: extremely anxious
Time frame: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at four weeks (before the 3rd menstrual phase), change from baseline (before tDCS) at five weeks (after the 3rd menstrual phase)
Beck Depression Inventory (BDI)
To assess depressive symptoms; from 0 to 63; score 0: not depressed, score 63: extremely depressed
Time frame: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at four weeks (before the 3rd menstrual phase), change from baseline (before tDCS) at five weeks (after the 3rd menstrual phase)
Pain Catastrophizing Scale (PCS)
To assess pain-maladaptive psychological status; from 0 to 52; score 0: not pain Catastrophizing , score 52: extremely pain Catastrophizing
Time frame: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at four weeks (before the 3rd menstrual phase), change from baseline (before tDCS) at five weeks (after the 3rd menstrual phase)
Long-form McGill Pain Questionnaire (MPQ)
To assess pain status; from 0 to 78; score 0: not painful, score 78: extremely painful
Time frame: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at four weeks (before the 3rd menstrual phase), change from baseline (before tDCS) at five weeks (after the 3rd menstrual phase)
Short-Form Health Survey (SF-36)
To assess quality of life; he SF-36 consists of eight scaled scores, which are the weighted sums of the questions in their section. Each scale is directly transformed into a 0-100 scale on the assumption that each question carries equal weight. From 0 to 100; score 0: equivalent to maximum disability, score 100: no disability.
Time frame: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at five weeks (after the 3rd menstrual phase)
Blood Hormones Measurement
To assess testosterone, progesterone, estrogen
Time frame: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at four weeks (before the 3rd menstrual phase)
Genotyping
To genotype the single nucleotide polymorphism genotyping (i.e., BDNF Val66Met polymorphism (rs6265), COMT Val158Met polymorphism (rs4680), OPRM1 (rs1799971), 5HTR2A (rs6313), SLC6A4 (rs25531)) from blood specimen
Time frame: baseline
Efficacy of tDCS blinding
To assure blinding efficacy; Patients do self-assessment about whether they receive real tDCS or sham tDCS. Assessment questionnaire:1 or 0. 1: real tDCS; 0: sham tDCS.
Time frame: At 1 months after tDCS intervention
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