Sound-Paired Vagus Nerve Stimulation for Tinnitus: A Safety and Feasibility Trial.

Summary

30 people with chronic pure-tone tinnitus were randomized to one of three noninvasive vagus nerve stimulation (VNS) protocols paired with tinnitus-matched sound: simultaneous VNS+sound, sound delayed 5 seconds after VNS onset (intended to engage parasympathetic conditioning), or randomly-timed VNS+sound (placebo), nine sessions over three weeks. No serious adverse events occurred and the paired protocol was feasible. Tinnitus loudness and the Tinnitus Functional Index did not differ between groups, but the delayed-sound group showed exploratory reductions in tinnitus unpleasantness, anxiety, and sleep problems, alongside EEG changes in regions involved in tinnitus and unpleasant-sound processing. The authors call the findings preliminary and say a fully powered trial with predefined efficacy outcomes is needed to confirm them.

Key findings

• Sound-paired noninvasive VNS was safe (no serious adverse events) and feasible over 9 sessions across 3 weeks.
• No significant between-group difference in tinnitus loudness or Tinnitus Functional Index.
• The delayed-sound (parasympathetic-conditioning) group showed exploratory reductions in tinnitus unpleasantness, anxiety, and sleep quality (Pittsburgh Sleep Quality Index).
• EEG changes were seen in regions involved in tinnitus and unpleasant-sound processing.
• Authors explicitly frame this as underpowered/exploratory, calling for a fully powered efficacy trial.