Is Transcranial Direct Current Stimulation an Effective Predictor for Invasive Occipital Nerve Stimulation Treatment Success in Fibromyalgia Patients?

Background: Fibromyalgia is a disorder distinguished by pervasive musculoskeletal pain that has pervasive effects on affected individuals magnifying the importance of finding a safe and viable treatment option.

Objective: The goal of this study is to investigate if transcranial direct current stimulation (tDCS) treatment can predict the outcome of occipital nerve field stimulation (ONFS) via a subcutaneous electrode.

Methods: Nine patients with fibromyalgia were selected fulfilling the American College of Rheumatology-90 criteria. The patients were implanted with a subcutaneous trial-lead in the C2 dermatome innervated by the occipital nerve. After the treatment phase of ONFS using a C2 implant, each patient participated in three sessions of tDCS. Stimulation outcomes for pain suppression were examined between the two methods to determine possible correlations.

Results: Positive correlation of stimulation effect was noted between the numeric rating scale changes for pain obtained by tDCS treatments and short-term measures of ONFS, but no correlation was noted between tDCS and long-term ONFS outcomes. A correlation also was noted between short-term ONS C2 implant pain suppression and long-term ONS C2 implant treatment success.

Conclusions: This pilot study suggests that tDCS is a predictive measure for success of OFNS in short-term but cannot be used as a predictive measure for success of long-term OFNS. Our data confirm previous findings that ONFS via an implanted electrode can improve fibromyalgia pain in a placebo-controlled way and exert a long-term pain suppression effect for ONFS via an implanted electrode.