Related Experiment Video
Updated: Feb 19, 2026
High-Definition Transcranial Direct Current Stimulation During Sleep
Published on: December 5, 2025
Randomized Controlled Trial of a Novel Device for Tinnitus Sound Therapy During Sleep
Sarah M Theodoroff1,2, Garnett P McMillan1, Tara L Zaugg1
1VA RR&D National Center for Rehabilitative Auditory Research, VA Portland Health Care System, OR.
Purpose:
The aim of this study was to determine if a customized stimulus from the Otoharmonics Levo System reduces tinnitus perceptions and reactions for people with bothersome tinnitus.
Method:
Sixty participants were randomized to 1 of 3 groups that used sound therapy devices during sleep that differed in their acoustic stimulus: (a) tinnitus-matched (TM), (b) noise stimulus (NS), and (c) bedside sound generator (BSG). Outcome measures were the Tinnitus Functional Index (TFI), numeric rating scale of tinnitus loudness, and tinnitus loudness match. A Bayesian hierarchical model was fit to estimate the differences in treatment efficacy among groups.
Results:
Average tinnitus reactions and perceptions improved across treatment groups. We are at least 87% certain that treatment with TM or NS reduces mean TFI compared to treatment with BSG, with an estimated relative efficacy of 4.5-5 points greater reduction. We are at least 95% certain that treatment with TM results in greater reduction in mean numeric rating scale (NRS) of tinnitus loudness compared to the other groups, with an estimated relative efficacy of about 0.75 points greater reduction.
Conclusions:
This study offers some support for greater average improvement in reactions to tinnitus with TM or NS devices compared to the BSG device. The TM group, compared to the BSG and NS groups, showed a greater reduction in ratings of tinnitus loudness on the NRS on average.
Supplemental Material:
https://doi.org/10.23641/asha.5545759.
