Comparison of Treatment Outcome between Repetitive Transcranial Magnetic Stimulation (rTMS) and Transcutaneous Direct Current Stimulation (tDCS) in Intractable Tinnitus

Abstract

Repetitive transcranial magnetic stimulation (rTMS) and transcutaneous direct current stimulation (tDCS) are non-invasive treatments for chronic tinnitus based on neuromodulation of cortical activity. Both are considered effective, but with heterogeneous results due to lack of established protocols. Because the target groups for both modalities overlap, it is difficult to recommend one of them. We tried to unify the inclusion criteria and treatment schedules to compare the two modalities. The medical charts of 36 patients who underwent rTMS as part of clinical routine were reviewed and data for 34 patients who underwent tDCS about 7 years later were collected prospectively. Both groups had chronic unilateral tinnitus refractory to medication. Patients were treated for 5 consecutive days, and tinnitus symptoms were evaluated by survey both at the end of the treatment schedule and 1 month after the treatment. The ratio of responders who showed >20% reduction in tinnitus handicap inventory scores were compared. At the end of the treatment, the rTMS group showed a rapid response compared to the tDCS group (rTMS, 30.6%; tDCS, 12.1%; p = 0.054). However, both groups showed a significant and similar reduction in tinnitus symptoms 1 month after the treatment (rTMS, 47.2%; tDCS, 36.4%; p = 0.618). As both groups showed comparable results for tinnitus reduction, tDCS may be superior in terms of cost-effectiveness.