Transcranial DC Stimulation Coupled With TENS for the Treatment of Chronic Pain: A Preliminary Study

ObjectiveBased on evidence showing that electrical stimulation of the nervous system is an effective method to decrease chronic neurogenic pain, we aimed to investigate whether the combination of 2 methods of electrical stimulation—a method of peripheral stimulation [transcutaneous electrical nerve stimulation (TENS)] and a method of noninvasive brain stimulation [transcranial direct current stimulation (tDCS)]—induces greater pain reduction as compared with tDCS alone and sham stimulation. MethodsWe performed a preliminary, randomized, sham-controlled, crossover, clinical study in which 8 patients were randomized to receive active tDCS/active TENS (“tDCS/TENS” group), active tDCS/sham TENS (“tDCS” group), and sham tDCS/sham TENS (“sham” group) stimulation. Assessments were performed immediately before and after each condition by a blinded rater. ResultsThe results showed that there was a significant difference in pain reduction across the conditions of stimulation (P=0.006). Post hoc tests showed significant pain reduction as compared with baseline after the tDCS/TENS condition [reduction by 36.5% (±10.7), P=0.004] and the tDCS condition [reduction by 15.5% (±4.9), P=0.014], but not after sham stimulation (P=0.35). In addition, tDCS/TENS induced greater pain reduction than tDCS (P=0.02). ConclusionsThe results of this pilot study suggest that the combination of TENS with tDCS has a superior effect compared with tDCS alone.