Dorsomedial Prefrontal Cortex Repetitive Transcranial Magnetic Stimulation for Tinnitus: Promising Results of a Blinded, Randomized, Sham-Controlled Study

Abstract

Tinnitus is the perception of sound in ears or head without corresponding external stimulus. Despite the great amount of literature concerning tinnitus treatment, there are still no evidence-based established treatments for curing or for effectively reducing tinnitus intensity. Sham-controlled studies revealed beneficial effects using repetitive transcranial magnetic stimulation (rTMS). Still, results show moderate, temporary improvement and high individual variability. Subcallosal area (ventral and dorsomedial prefrontal and anterior cingulate cortices) has been implicated in tinnitus pathophysiology. Our objective is to evaluate the use of bilateral, high frequency, dorsomedial prefrontal cortex (DMPFC) rTMS in treatment of chronic subjective tinnitus. Randomized placebo-controlled, single-blinded clinical trial. Twenty sessions of bilateral, 10 Hz rTMS at 120% of resting motor threshold of extensor hallucis longus were applied over the DMPFC. Fourteen patients underwent sham rTMS and 15 were submitted to active stimulation. Tinnitus Handicap Inventory (THI), visual analog scale, and tinnitus loudness matching were obtained at baseline and on follow-up visits. The impact of intervention on outcome measures was evaluated using mixed-effects restricted maximum likelihood regression model for longitudinal data. A difference of 11.53 points in the THI score was found, favoring the intervention group (p = 0.05). The difference for tinnitus loudness matching was of 4.46 dB also favoring the intervention group (p = 0.09). Tinnitus treatment with high frequency, bilateral, DMPFC rTMS was effective in reducing tinnitus severity measured by THI and matched tinnitus loudness when compared to sham stimulation.