Electric field-navigated transcranial magnetic stimulation for chronic tinnitus: a randomized, placebo-controlled study

Abstract

<p><i>Objective</i>: Repetitive transcranial magnetic stimulation (rTMS) may alleviate tinnitus. We evaluated effects of electric field (E-field) navigated rTMS targeted according to tinnitus pitch. No controlled studies have investigated anatomically accurate E-field-rTMS for tinnitus. <i>Design</i>: Effects of E-field-rTMS were evaluated in a prospective randomised placebo-controlled 6-month follow-up study on parallel groups. Patients received 10 sessions of 1 Hz rTMS or placebo targeted to the left auditory cortex corresponding to tonotopic representation of tinnitus pitch. Effects were evaluated immediately after treatment and at 1, 3 and 6 months. Primary outcome measures were visual analogue scores (VAS 0–100) for tinnitus intensity, annoyance and distress, and the Tinnitus Handicap Inventory (THI). <i>Study sample:</i> Thirty-nine patients (mean age 50.3 years). <i>Results</i>: The mean tinnitus intensity (<i>F</i>₃ = 15.7, <i>p</i> < 0.0001), annoyance (<i>F</i>₃ = 8.8, <i>p</i> = 0.0002), distress (<i>F</i>₃ = 9.1, <i>p</i> = 0.0002) and THI scores (<i>F</i>₄ = 13.8, <i>p</i> < 0.0001) decreased in both groups over time with non-significant differences between the groups. After active rTMS, 42% and 37% of the patients showed excellent response at 1 and 3 months against 15% and 10% in the placebo group (<i>p</i> = 0.082 and <i>p</i> = 0.065). <i>Conclusions</i>: Despite the significant effects of rTMS on tinnitus, differences between active and placebo groups remained non-significant, due to large placebo-effect and wide inter-individual variation.</p