Transcranial DC stimulation in fibromyalgia: optimized cortical target supported by high-resolution computational
Mariana E Mendonca1, Marcus B Santana, Abrahão F Baptista
1Bahiana School of Medicine and Public Health, Salvador, BA, Brazil.
The Journal of Pain
|April 19, 2011
Summary
Optimizing transcranial direct current stimulation (tDCS) for fibromyalgia pain relief depends on electrode placement. Supra-orbital montages show analgesic effects by directing current to pain-related brain areas.
Area of Science:
- Neuroscience
- Pain Management
- Medical Devices
Background:
- Fibromyalgia is a chronic pain condition with limited treatment options.
- Transcranial direct current stimulation (tDCS) is an emerging neuromodulation technique for pain management.
- The efficacy of tDCS may depend on electrode montage and induced current flow.
Purpose of the Study:
- To investigate the distribution of electrical current and short-term analgesic effects of tDCS in fibromyalgia patients.
- To correlate clinical outcomes with computational models of current flow for different electrode montages.
Main Methods:
- Thirty fibromyalgia patients were randomized into five groups (Cathodal-M1, Cathodal-SO, Anodal-M1, Anodal-SO, Sham).
- tDCS (2 mA, 20 minutes) was applied using various extracephalic electrode montages.
- Pain was assessed using Visual Numerical Scale (VNS), Pressure Pain Threshold (PPT), and Body Diagram (BD).
- Magnetic Resonance Imaging (MRI)-derived Finite Element Method (FEM) models predicted cortical current flow.
Main Results:
- Significant pain reduction was observed in the cathodal-SO and anodal-SO groups based on VNS scores.
- A trend towards improved PPT was noted in the anodal-SO group.
- Computational models showed M1-extracephalic montage resulted in temporo-parietal current flow, with no clinical effect.
- SO-extracephalic montage induced current flow in anterior prefrontal areas, correlating with analgesic effects.
Conclusions:
- Electrode montage is critical for tDCS-induced analgesia in fibromyalgia.
- The location of induced electrical current, particularly in relation to the pain matrix, significantly influences tDCS efficacy.
- Future tDCS pain studies should carefully consider electrode placement for optimal outcomes.
