Is There an Optimal Repetitive Transcranial Magnetic Stimulation Target to Treat Chronic Tinnitus?

Abstract

Chronic tinnitus is a clinical symptom that affects 10% to 15% of the adult population. Repetitive transcranial magnetic stimulation (rTMS) is a promising treatment, but significant heterogeneity exists in the treatment outcomes and stimulation parameters. In this study, we perform a qualitative systematic review to determine if there is an optimal rTMS site to treat tinnitus. A literature search was performed by searching the MEDLINE, Embase, Web of Science, and Cochrane databases. Sham-controlled studies in adults were included that contained >10 patients with tinnitus for >3 months and utilized 10 to 20 electroencephalography coordinates. Study outcomes were considered positive if the treatment arm reported a significant reduction in the primary tinnitus score relative to sham. There were 1211 studies screened. Nineteen studies met the inclusion criteria, and 8 unique stimulation sites were reported. Studies had 53.7 ± 46.0 patients (mean ± SD). The mean duration of follow-up was 10.3 ± 9.6 weeks. Positive outcomes regarding tinnitus suppression were reported in 5 of 5 (100%) studies stimulating the temporoparietal junction midway between T3 and P3 or between T4 and P4. Tinnitus suppression at all other sites was less frequent with a combined success rate of only 8 of 14 (57.1%). Significant heterogeneity exists in the literature in regard to the optimal transcranial magnetic stimulation target. These preliminary findings suggest that the temporoparietal junction midway between T3 and P3 or T4 and P4 is a promising nonauditory rTMS target in the setting of chronic tinnitus. Future research should elucidate the effectiveness of this site for tinnitus suppression.