Primary Outcomes

Description: pain scale; from 0 to 10; score 0: no pain, score 10: unbearable pain

Measure: Visual Analog Scale (VAS)

Time: 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)

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Description: Resting-state functional magnetic resonance imaging (rs-fMRI) is a well established method of functional magnetic resonance imaging (fMRI) that is used to evaluate regional interactions in the brain that occur in a resting (task-negative) state, when a subject is not performing an explicit task. Functional connectivity is the connectivity between brain regions that share functional properties, it can be defined as the correlation between spatially remote neurophysiological events, expressed as the neural networks of brain.

Measure: Functional connectivity of rs-fMRI Imaging

Time: 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)

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Secondary Outcomes

Description: 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.

Measure: Quantitative sensory testing (QST)

Time: 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)

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Description: To assess anxious symptoms; from 20 to 80; score 20: not anxious, score 80: extremely anxious

Measure: Spielberger State-Trait Anxiety Inventory (STAI)

Time: 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)

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Description: To assess anxious symptoms; from 0 to 63; score 0: not anxious, score 63: extremely anxious

Measure: Beck Anxiety Inventory (BAI)

Time: 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)

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Description: To assess depressive symptoms; from 0 to 63; score 0: not depressed, score 63: extremely depressed

Measure: Beck Depression Inventory (BDI)

Time: 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)

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Description: To assess pain-maladaptive psychological status; from 0 to 52; score 0: not pain Catastrophizing , score 52: extremely pain Catastrophizing

Measure: Pain Catastrophizing Scale (PCS)

Time: 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)

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Description: To assess pain status; from 0 to 78; score 0: not painful, score 78: extremely painful

Measure: Long-form McGill Pain Questionnaire (MPQ)

Time: 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)

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Description: 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.

Measure: Short-Form Health Survey (SF-36)

Time: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at five weeks (after the 3rd menstrual phase)

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Description: To assess testosterone, progesterone, estrogen

Measure: Blood Hormones Measurement

Time: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at four weeks (before the 3rd menstrual phase)

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Description: 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

Measure: Genotyping

Time: baseline

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Description: 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.

Measure: Efficacy of tDCS blinding

Time: At 1 months after tDCS intervention

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Primary Outcomes

Description: pain scale; from 0 to 10; score 0: no pain, score 10: unbearable pain

Measure: Visual Analog Scale (VAS)

Time: 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)

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Description: 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.

Measure: Somatosensory evoked magnetic fields to experimental pain

Time: 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)

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Secondary Outcomes

Description: 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.

Measure: Quantitative sensory testing (QST)

Time: 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)

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Description: To assess anxious symptoms; from 20 to 80; score 20: not anxious, score 80: extremely anxious

Measure: Spielberger State-Trait Anxiety Inventory (STAI)

Time: 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)

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Description: To assess anxious symptoms; from 0 to 63; score 0: not anxious, score 63: extremely anxious

Measure: Beck Anxiety Inventory (BAI)

Time: 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)

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Description: To assess depressive symptoms; from 0 to 63; score 0: not depressed, score 63: extremely depressed

Measure: Beck Depression Inventory (BDI)

Time: 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)

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Description: To assess pain-maladaptive psychological status; from 0 to 52; score 0: not pain Catastrophizing , score 52: extremely pain Catastrophizing

Measure: Pain Catastrophizing Scale (PCS)

Time: 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)

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Description: To assess pain status; from 0 to 78; score 0: not painful, score 78: extremely painful

Measure: Long-form McGill Pain Questionnaire (MPQ)

Time: 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)

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Description: 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.

Measure: Short-Form Health Survey (SF-36)

Time: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at five weeks (after the 3rd menstrual phase)

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Description: To assess testosterone, progesterone, estrogen

Measure: Blood Hormones Measurement

Time: change from baseline (before tDCS) at one week (after tDCS completion), change from baseline (before tDCS) at four weeks (before the 3rd menstrual phase)

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Description: 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

Measure: Genotyping

Time: baseline

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Description: 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.

Measure: Efficacy of tDCS blinding

Time: At 1 months after tDCS intervention

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Primary Outcomes

Description: Between-group difference of binding potential of [18 Fluorine]-altanserin ([18F]-altanserin) and [11 Carbon]-3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile ([11C]-DASB) ([11C]-DASB)

Measure: Difference in binding potential of [18 Fluorine]-altanserin ([18F]-altanserin) and [11 Carbon]-3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile ([11C]-DASB) ([11C]-DASB)

Time: 2-3 days

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Secondary Outcomes

Description: The Ardouin Scale of Behavior in Parkinson's Disease (ASBPD) evaluates hypo- and hyperdopaminergic behaviors and can also detect and quantify neuropsychiatric fluctuations by evaluating OFF-drug dysphoria and ON-drug euphoria. It is based on a semi-structured interview that encompasses the whole spectrum of behavioral spectrum from hypo-to hyperdopaminergic syndromes as well as non-motor fluctuations. The scale consists of 18 items addressing non-motor symptoms, grouped in four parts: general psychological evaluation, apathy, non-motor fluctuations and hyperdopaminergic behaviors. The rating in five points (0-4 from absent to severe) is carried out during a semi-structured interview. Open-ended questions introduce each item, allowing patients to express themselves as freely as possible. Close-ended questions permit the rating of severity and intensity.

Measure: Ardouin Scale of Behavior in Parkinson's Disease (ASBPD)

Time: 2-3 days

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Description: The Questionnaire For Impulsive-Compulsive Disorders In Parkinson's Disease-Rating Scale (QUIP-RS) is designed to measure severity of symptoms and support a diagnosis of impulse control disorders and related disorders in Parkinson's Disease (PD). The QUIP-RS is administered with an instruction sheet that provides examples of the behaviors being assessed and a brief description of the categories for frequency (never [0] = not at all, rarely [1] = infrequently or 1 day/week, etc.). Scores for each Impulsive Compulsive Disorder (ICD) and related disorder range from 0 to 16, with a higher score indicating greater severity (frequency) of symptoms. The total QUIP-RS score for all ICDs and related disorders combined ranges from 0 to 112.

Measure: Questionnaire For Impulsive-Compulsive Disorders In Parkinson's Disease-Rating Scale (QUIP-RS)

Time: 2-3 days

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Description: The full version of the UPPS-P Scale is composed of 59 items, with 10-14 items per scale. Items are scored on a 4-point scale: Agree Strongly = 1 Agree Some = 2 Disagree Some = 3 Disagree Strongly = 4 Higher values translate into higher levels of impulsivity. The results allow assessement of the patient according to five impulsive personality traits: Negative urgency: tendency to act rashly under extreme negative emotions Lack of Premeditation: tendency to act without thinking Lack of Perseverance: inability to remain focused on a task Sensation Seeking: tendency to seek out novel and thrilling experiences Positive Urgency: tendency to act rashly under extreme positive emotions

Measure: Urgency, Premeditation (lack of), Perseverance (lack of), Sensation Seeking Impulsive Behavior Scale (UPPS Impulsive Behavior Scale)

Time: 2-3 days

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Description: The MDS-UPDRS is composed of four parts, namely, I: Non-motor Experiences of Daily Living; II: Motor Experiences of Daily Living; III: Motor Examination; IV: Motor Complications and includes 65 items. Each question has five responses that are linked to commonly accepted clinical terms: 0 = normal, 1 = slight, 2 = mild, 3 = moderate, and 4 = severe. The overall progression of disability is given a score ranging from 0 = no disability 1= slight disability 2= moderate disability 3= high disability and 4= severe disability.

Measure: Movement Disorder Society (MDS) Unified Parkinson's Disease Rating Scale (MDS-UPDRS)

Time: 2-3 days

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Description: The Beck Depression Inventory (BDI-II) is used to measure the severity of depression. It contains 21 questions, each answer being scored on a scale value of 0 to 3. Higher total scores indicate more severe depressive symptoms: 0-13: minimal depression 14-19: mild depression 20-28: moderate depression 29-63: severe depression.

Measure: Beck Depression Inventory II (BDI-II)

Time: 2-3 days

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Description: For this scale, patients are asked to answer 14 questions, each of which is scored on a 4-point scale of 0-3, and apathy is rated as more severe as the total score (0-42) increases.

Measure: Starkstein Apathy Scale (SAS)

Time: 2-3 days

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Description: The State-Trait Anxiety Inventory measures anxiety by assessing someone's state (S) and trait (T) anxiety at the same time. Its combined format consists of 40 questions. The S-Anxiety scale (STAI Form Y-1) consists of twenty statements that evaluate how the respondent feels "right now, at this moment". The T- Anxiety scale (STAI Form Y-2) consists of twenty statements that evaluate how the respondent feels "generally". In responding to the S-Anxiety scale, the subjects choose the number that best describes the intensity of their feelings: (1) not at all, (2) somewhat, (3) moderately, (4) very much so. In responding to the T-Anxiety scale, subjects rate the frequency of their feelings on the following four-point scale: (1) almost never, (2) sometimes, (3) often, (4) almost always. Each STAI item is given a weighted score of 1 to 4. Scores for both the S-Anxiety and the T-Anxiety scales can vary from a minimum of 20 to a maximum of 80 with higher scores correlating to higher anxiety.

Measure: State-Trait Anxiety Inventory -Y (STAI-Y)

Time: 2-3 days

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Description: The SHAPS measures the subject's ability to experience pleasure (hedonic tone) and its absence (anhedonia). It consists of 14 items with 4 possible responses: Definitely Agree, Agree, Disagree, Definitely Disagree. A score from 0- 14 is possible (1 point for each response in the Disagree category and 0 points for each response in the Agree category). The higher the score the less the subject is able to experience pleasure.

Measure: Snaith-Hamilton Pleasure Scale (SHAPS)

Time: 2-3 days

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Description: Measure specifically designed to capture the anticipatory and consummatory facets of pleasure. It consists of 10 questions assessing anticipatory pleasure (TEPS-ANT) and 8 questions assessing consummatory pleasure (TEPS-CON) using a 6-point fixed choice response format ranging from 1 = very false for me to 6 = very true for me. The higher the score for each section, the more the subject experiences anticipatory pleasure and consummatory pleasure, respectively.

Measure: Temporal Experience of Pleasure Scale (TEPS)

Time: 2-3 days

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Description: Stop Signal Task

Measure: Stop Signal Reaction Time (SSRT)

Time: 2-3 days

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Description: 27-item Monetary Choice Questionnaire: for each question, patients will choose between two different monetary values (a high monitary value versus a low monitary value) in order to determine the patient's level of impulsiveness.

Measure: Discounting rate

Time: 2-3 days

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Description: 4 Choice Serial Reaction Time Task

Measure: Proportion of premature responses

Time: 2-3 days

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Description: Polymorphism rs6313 also called T102C or C102T is a gene variation, a single nucleotide polymorphism (SNP) in the human Hydroxytryptamine Receptor 2A (HTR2A) gene that codes for the 5-HT2A receptor. The SNP is a synonymous substitution located in exon 1 of the gene where it is involved in coding the 34th amino acid as serine.

Measure: Polymorphism rs6313 (or T102C) of the serotonin 5-Hydroxytryptamine 2A (5-HT2A) receptor

Time: 2-3 days

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Description: Polymorphism 5-HydroxyTryptamine (serotonin) Transporter Gene-Linked Polymorphic Region (5-HTTLPR)/rs25531 of the serotonin transporter (SERT)

Measure: Polymorphism 5-HydroxyTryptamine (serotonin) Transporter Gene-Linked Polymorphic Region (5-HTTLPR)/rs25531 of the serotonin transporter (SERT)

Time: 2-3 days

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Description: Anatomical imaging using a T1-weighted Magnetization-Prepared RApid Gradient-Echo (T1_MPRAGE) sequence for morphometry.

Measure: Magnetic Resonance Imaging metrics: anatomical imaging

Time: 2-3 days

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Description: Diffusion weighted imaging for Diffusion Tensor Imaging (DTI) and tractography

Measure: Magnetic Resonance Imaging metrics: Diffusion Weighted imaging

Time: 2-3 days

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Description: Resting State Functional Imaging for functional connectivity

Measure: Magnetic Resonance Imaging metrics: Resting State Functional Imaging

Time: 2-3 days

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