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
Barcelona, whether a trauma-oriented therapy, Eye Movement Desensitization Reprocessing
(EMDR), in combination with a non-invasive brain stimulation technique, transcranial
Direct Current Stimulation (tDCS), can improve typical FM symptoms.
Outcomes
Primary outcomes:
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.
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:
To test whether the EMDR plus tDCS or EMDR plus sham-tDCS in comparison 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
Rheumatology Department of the Parc de Salut Mar responsible for patient recruitment, and
the Cognitive Neuro-Lab of the Universitat Oberta de Catalunya for guidance and council
on tDCS use.
Design
Within a double-blind randomized controlled design, patients will be randomized to one of
the following three treatment arms:
EMDR with tDCS (20 sessions) vs EMDR with sham-tDCS (20 sessions) vs TAU.
Psychotherapists, raters, and patients will be kept blind for tDCS treatment conditions
until the end of the trial.
Participants
The patient sample will consist of 96 females fulfilling the 2016 American College of
Rheumatology criteria for FM based on clinical interview (Wolfe et al, 2010).
Interventions
Randomizations
Participants were randomly assigned to one of the three study groups using REDCap's
stratified randomization module to ensure balanced allocation in terms of Revised
Fibromyalgia Impact Questionnaire (FIQ-R) score and education level. When a new
participant is enrolled, REDCap identifies their stratum based on the data for these two
variables, then it assigns them to a study arm using block randomization within that
stratum, favoring the arm with the fewest current assignments to maintain balance. The
allocation sequence is concealed from outcome raters until participants have finished the
trial. This randomization module enforces balance by prioritizing equal group sizes
within strata, even with uneven stratum sizes, it provides real-time adaptations by
adjusting assignments dynamically as participants enroll and it logs all randomization
events for reproducibility purposes.
Computation of sample size
The main tests of the study will consist of assessing whether patients assigned to EMDR
show different levels in the pain intensity variable using a standard formula for
two-tailed t-tests. The total sample size required to detect large to very large effect
size differences (Cohen's d ≥ 1) between three groups with a significance level of 0.05
and statistical power of 80% is 28. Assuming 15% dropouts, we will aim to randomize 96
patients, meaning 32 per group.
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.
