Augmentation of EMDR With tDCS in the Treatment of Fibromyalgia

Fibromyalgia (FM) is a generalized, widespread chronic pain disorder and has an estimated prevalence of 2%-4% in the general population. Current pharmacological and psychological interventions frequently produce limited benefits in FM patients. Due to FM's strong association with psychological trauma causing neurobiological alterations in stress response, a trauma-focused psychotherapy is an innovative alternative treatment option. Eye Movement Desensitization and Reprocessing (EMDR) has been recognized by the World Health Organization as a first-line therapeutic tool for post-traumatic stress disorder and first evidence suggests that it is also beneficial for patients with FM. Given the complex etiology of FM, a combination of psychotherapy with other treatment options can maximize a potential therapeutic success. A possible candidate herby is Multifocal transcranial Direct Current Stimulation (tDCS), a non-invasive stimulation technique, which can modify neural activities related to pain and which has shown short-term positive effects on chronic pain and quality of life in FM patients. The patient sample will consist of 45 female patients meeting 2016 American College of Rheumatology criteria for FM based on a clinical interview. They will be randomized to 20 sessions of EMDR plus tDCS or EMDR plus sham-tDCS, or Treatment as Usual (TAU). Therapists, raters, and patients will be kept blind to MtCS treatment conditions. Evaluations will be at baseline, post treatment at 6 months, and follow-up at 12 months. Hypotheses are that EMDR improves pain intensity and clinical symptoms at short and long-term, and that tDCS enhances this effect, which will be superior to tDCS-sham.

Fibromyalgia (FM) affects 2-4% of the general population with typical symptoms such as generalized and widespread pain, sleep disturbances, problems in memory and attention, anxiety and depression. Pharmacological treatment and psychotherapeutic interventions have produced limited effects so far. Interestingly, lifetime psychosocial adversities are substantially elevated in FM but no interventions are currently offered. Given the complex etiology of FM, combining a psychotherapy with other treatment options can maximize the potential benefit of this intervention. The investigators will test in a marginalized catchment area in Barcelona, whether a trauma-oriented therapy, Eye Movement Desensitization Reprocessing (EMDR), in combination with a non-invasive brain stimulation technique, Multifocal transcranial Direct Current Stimulation (tDCS), can improve typical FM symptoms.

Outcomes

Primary outcomes:

1. To test whether EMDR plus tDCS or EMDR plus sham-tDCS in comparison to TAU group, improve pain intensity, depressive and anxious symptoms and trauma associated symptoms after therapy and follow-up.
2. To test whether an improvement in pain intensity, depressive and anxious symptoms and trauma associated symptoms can be augmented by simultaneous tDCS comparing EMDR plus tDCS with EMDR plus sham-tDCS after the intervention and whether this is maintained at the follow-up visit.

   Secondary outcomes:
3. To test whether the EMDR plus tDCS or EMDR plus sham-tDCS incomparison to TAU group, improves more in subjective wellbeing after the treatment, and whether this is maintained at the follow-up visit.

Indicators to monitor clinical changes will be performed via various standard self- and hetero-applied scales by blind-to-treatment raters and information provided by patients and the medical chart IT system of our catchment area at baseline (visit 1), post treatment at 6 months (visit 2), and follow-up evaluation at 12 months (visit 3).

This multicenter collaborative project will involve the participation of the Psychiatric Department of the Parc de Salut Mar responsible for coordinating the study, the Rheumatologist Department of the Parc de Salut Mar responsible for patient recruitment, the Institut d'investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) responsible for randomization and data base management, and the Cognitive Neuro-Lab responsible for the MtCS stimulation.

Design

Within a double-blind randomized controlled design, patients will be randomized to one of the following three treatment arms:

EMDR with MtCS (20 sessions) vs EMDR with sham-MtCS (20 sessions) vs TAU. Psychotherapists, raters, and patients will be kept blind for MtCS treatment conditions until the end of the trial.

Participants

The patient sample will consist of 45 females fulfilling the 2016 American College of Rheumatology criteria for FM based on clinical interview (Wolfe et al, 2010).

Interventions

* EMDR therapy
* Multifocal transcranial Current Stimulation (MtCS)
* Treatment as Usual

Randomizations

The main analysis will be the comparison between patients assigned to EMDR vs not assigned to EMDR, and the secondary analysis will be, among patients assign to EMDR, the comparison between patients with FM assigned to active MtCS vs patients with FM assigned to sham MtCS. Therefore, the investigators will not randomly assign the individuals to one of the three arms but, rather, will randomize patients meeting the inclusion criteria twice: they will first randomize them to EMDR vs non-EMDR, and then will randomize those in the EMDR group to active MtCS or sham MtCS. For the sake of brevity, the investigators describe here only the randomization to EMDR vs non-EMDR, because the randomization to active MtCS vs. sham MtCS is identical. The first two patients will be randomly allocated to EMDR with p=2/3. For each subsequent patient, the following biased coin algorithm will be applied. If a group includes at least two more patients than it would have to have to maintain the ratio 2 EMDR / 1 control, the patient will be randomly assigned to the other group with p=0.6. Otherwise, the researchers will simulate that the new patient is allocated to EMDR and calculate the between-group standardized difference in pain intensity variable, will then simulate that the new patient is allocated to non-EMDR and recalculate the difference, and finally randomly allocate the patient to the group associated to the smallest difference with p=0.6. This strategy decreases prognostic imbalances between groups because it decreases differences in potential confounders but it still includes randomization.

Computation of sample size

The main tests of the study will consist in assessing whether patients assigned to EMDR show different levels of pain intensity variable using standard formula, the total sample size required to detect large to very large effect size differences (Cohen's d ≥ 1) between two groups with a significance level of 0.05 is 13 and 26. Assuming 15% dropouts, the researchers will aim to randomize 45 patients, i.e. 15 and 30 per arm.

Statistical Analysis

The distribution of socio-demographic and clinical characteristics between groups at baseline will be summarized using descriptive statistics. The change in clinical and functional variables from the baseline evaluation to post intervention will be analyzed using linear model t-tests, including as regressors of no interest the potential confounders (age, pain score, anxiety and depression severity, and number of years in education). The statistical software used for the analysis will be the latest available version of R. The investigators will conduct an intention to treat (ITT) analysis, and will use the "Last Observation Carried Forward" (LOCF) method for losses at follow-up.

Eligibility Criteria:
Inclusion Criteria:

* Age between 18 and 70 years old
* Mean pain score of at least 4 on the visual analog scale (VAS) in the two weeks preceding the clinical trial
* Presence of one or more traumatic events causing current trauma-related symptoms
* Current clinical symptoms of depression and/or anxiety
* 2 weeks of stable medication

Exclusion Criteria:

* Comorbid autoimmune or chronic inflammatory disease
* Neurological or serious medical diseases
* Bipolar disorder, schizoaffective disorder and schizophrenia
* Suicidal ideation
* Previous EMDR therapy
* Substance abuse/dependency within 1 month prior to participation (except for nicotine abuse/dependency),
* Pending FM-related litigation or disability
* Metallic implants in the head
* Positive test for pregnancy