Adjunctive role of bifrontal transcranial direct current stimulation in distressed patients with severe tinnitus

Background: This study assessed the therapeutic effect of adjunctive bifrontal transcranial direct current stimulation (tDCS) in patients with tinnitus. Methods: Forty-four patients who visited our university hospital with a complaint of non-pulsatile subjective tinnitus in January through December 2016 were enrolled. All patients received directive counseling and sound therapy, such as a sound generator or hearing aids, and/or oral clonazepam. Patients who agreed to undergo additional bifrontal tDCS were classified as the study group (n = 26). For tDCS, 1.5 mA of direct current was applied to the prefrontal cortex with a 10-20 EEG system for 20 minutes per session. Results: The Tinnitus Handicap Inventory (THI), Beck Depression Inventory, and Visual Analog Scale (VAS) scores decreased significantly after treatment (P < 0.001). Patients who had a moderate or catastrophic handicap were significantly more likely to respond favorably to bifrontal tDCS (P = 0.026). There was no correlation of number of tDCS sessions with change in the THI or VAS score (P > 0.05). Logistic regression analysis revealed that the initial THI score was independently associated with improvement in the THI. However, tDCS was not a significant determinant of recovery. Conclusion: tDCS can be used as an adjunctive treatment in patients with severe tinnitus. Although tDCS did not decrease the loudness of tinnitus, it could alleviate the distress associated with the condition in some patients with a moderate or catastrophic handicap.