EFFECTIVENESS AND SAFETY OF TRANSCRANIAL DIRECT CURRENT STIMULATION IN FIBROMYALGIA: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: To evaluate the effectiveness and safety of transcranial direct current stimulation for fibromyalgia. Methods: Databases, conference records and registered trials were searched for articles published from the date of establishment of the database through to October 2015. Six randomized controlled trials (n=192) of transcranial direct current stimulation for fibromyalgia were included in the current study. Data extraction: Two researchers independently screened the literature, assessed methodological quality using the Cochrane Collaboration's tool, and extracted data. Data synthesis: Studies were divided into 3 groups for meta-analysis according to stimulation site and polarity. Significant improvement in pain and general fibromyalgia-related function was seen with anodal transcranial direct current stimulation over the primary motor cortex (p<0.05). However, the pressure pain threshold did not improve (p>0.05). Anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex did not significantly reduce pain or improve general fibromyalgia-related function compared with sham stimulation (p>0.05). Cathodal transcranial direct current stimulation over the primary motor cortex did not improve the pressure pain threshold compared with sham stimulation (p>0.05). No significant adverse effects were seen. Conclusion: Anodal transcranial direct current stimulation over the primary motor cortex is more likely than sham transcranial direct current stimulation to relieve pain and improve general fibromyalgia-related function.