The International Tinnitus Journal

Suppression of Severe Tinnitus Via Acute Electrical Stimulation of The Round Window Niche: A Randomized Controlled Trial

Introduction: At present, no current pharmacological or surgical interventions have been approved for the treatment of debilitating tinnitus. Since the late 1970s, it has been known that electrical stimulation of the cochlea can achieve partial or complete suppression of tinnitus percepts. This effect is also widely observed in users of cochlear implants. For individuals without concomitant severe-to-profound deafness, cochlear implantation is not a realistic option. Here we evaluated a promontory round window electrical stimulation device (PromStim, MED-EL, Innsbruck, Austria) as a potential treatment for severe tinnitus. Methods: 30 participants with grade 5 tinnitus were randomized into either an intervention or control group (n=15 each). All participants underwent myringotomy or micro flap surgery under local anesthesia. A stimulating electrode was placed at the round window niche. In the intervention group, stimulation was performed with biphasic pulses delivered at a rate of 100 or 5000 Hz. Stimulation was initially performed at an amplitude of 100 μA and incrementally increased. The control group underwent sham stimulation. The Tinnitus Handicap Inventory (THI) and a visual analog scale (VAS) of tinnitus severity were administered to all participants before and after the procedure. Results: In the intervention group, 9/15 participants (60%) had total suppression, 4/15 (26.6%) had partial suppression, and 2/15 (13.3%) had no suppression. In the control group, 2/15 participants (13.3%) had partial suppression and 13/15 (86.6%) had no suppression. After treatment, tinnitus severity was reduced to grade 4 in 10/15 participants (66.6%) in the intervention group and in 1/15 participants (6.6%) in the control group. Mean VAS scores of tinnitus severity were also reduced in the intervention group after stimulation. The mean duration of residual inhibition was 24.9 hours. Conclusion: Electrical stimulation of the round window niche can induce rapid and sustained suppression of tinnitus percepts, accompanied by reductions in self-reported severity. This may be a useful method for tinnitus control when cochlear implantation is not an option.