Clinically Effective Treatment of Fibromyalgia Pain With High-Definition Transcranial Direct Current Stimulation: Phase II Open-Label Dose Optimization

Abstract

Despite promising preliminary results in treating fibromyalgia (FM) pain, no neuromodulation technique has been adopted in clinical practice because of limited efficacy, low response rate, or poor tolerability. This phase II open-label trial aims to define a methodology for a clinically effective treatment of pain in FM by establishing treatment protocols and screening procedures to maximize efficacy and response rate. High-definition transcranial direct current stimulation (HD-tDCS) provides targeted subthreshold brain stimulation, combining tolerability with specificity. We aimed to establish the number of HD-tDCS sessions required to achieve a 50% FM pain reduction, and to characterize the biometrics of the response, including brain network activation pain scores of contact heat-evoked potentials. We report a clinically significant benefit of a 50% pain reduction in half (n = 7) of the patients (N = 14), with responders and nonresponders alike benefiting from a cumulative effect of treatment, reflected in significant pain reduction (P = .035) as well as improved quality of life (P = .001) over time. We also report an aggregate 6-week response rate of 50% of patients and estimate 15 as the median number of HD-tDCS sessions to reach clinically meaningful outcomes. The methodology for a pivotal FM neuromodulation clinical trial with individualized treatment is thus supported.

Delayed pain decrease following M1 tDCS in spinal cord injury: A randomized controlled clinical trial

“…It has been shown that a minimum of 10-20 sessions of tDCS need to be performed in order to induce relevant clinical improvements [39][40][41][42]. However, in clinical trials involving patients with severe disabilities, such as SCI as in the present study, we experienced a high rate of drop-out which limits the power of clinical results.…”

Efficacy of transcranial direct current stimulation over primary motor cortex (anode) and contralateral supraorbital area (cathode) on clinical pain severity and mobility performance in persons with knee osteoarthritis: An experimenter- and participant-blinded, randomized, sham-controlled pilot clinical study

“…In contrast, some studies found that M1-SO applied tDCS does not improve clinical pain outcomes [53]. Five sessions could be underdosing and may have limited treatment effects [54]. However, it is important to note that the efficacy of M1-SO tDCS depends on a number of factors, including the intensity and duration of stimulation, the polarity of the electrode, the target brain area, electrode preparation methods, and the target population [18].…”

Neural signature of tDCS, tPCS and their combination: Comparing the effects on neural plasticity

“…Another possible explanation could be a type II error (β), since these measurements were secondary outcomes and our sample size was powered to detect qEEG differences. In addition, it should be noted that current literature on tDCS has shown that repetitive sessions are required in order to induce larger effects [36,37]. Therefore, a single stimulation session might not be enough to generate important clinical changes.…”