Transcutaneous Electrical Nerve Stimulation for Treatment of Tinnitus: A Systematic Review and Meta-Analysis.

OBJECTIVE To evaluate the treatment efficacy of transcutaneous electrical nerve stimulation (TENS) in patients with tinnitus. DATA SOURCES PubMed, Scopus, Web of Science, and Cochrane Library were searched for the following concepts: "Transcutaneous Electric Nerve Stimulation" and "Tinnitus." STUDY SELECTION Inclusion: 1) double- or single-blinded randomized controlled trials; 2) double- or single-blinded randomized comparison trials; 3) prospective or retrospective observational studies; and 4) case series. Exclusion: Non-English studies, nonhuman studies, case reports (n ≤ 5), and review articles. DATA EXTRACTION Tinnitus Handicap Inventory (THI), the Visual Analog Scale (VAS), and perceived tinnitus suppression after treatment. Additional data collected included tinnitus laterality, duration of symptoms, location of electrode placement, time to follow-up, etiology of tinnitus, and treatment side effects. DATA SYNTHESIS The literature search yielded 2941 unique articles. After reviewing 118 full-text articles, 17 studies reporting on 1,215 patients were included for final analysis. Four studies provided data available for meta-analysis of pre- and posttreatment THI and VAS (Cochrane Review Manager). TENS showed significant overall reduction on THI (-7.55 [-10.93 to -4.18], p < 0.0001) and VAS (-0.65 [-0.99 to -0.30], p < 0.0002). Subjective improvement of tinnitus was pooled across 13 studies using meta-analysis of proportions (MedCalc). Tinnitus suppression occurred in 40.0% [28.9-51.7%] patients. Among those who responded, 22.2% [12.2-29.7%] experienced complete suppression and 10.2% [0.2-31.9%] experienced persistent improvement at 3 months. CONCLUSIONS TENS represents a safe and feasible treatment option for tinnitus and might be a worthy consideration among the spectrum of interventions developed for tinnitus.