Pilot evaluation of transcutaneous vagus nerve stimulation in chronic tinnitus: clinical outcomes and DTI insights

This study aims to evaluate the effectiveness of tVNS treatment in individuals with subjective chronic tinnitus. This pilot study included a total of 13 individuals (6 female and 7 male) aged 25–50 years (41.46 ± 8.04 years) who had complained of subjective tinnitus for at least two years. All participants underwent audiological evaluations, including assessments of tinnitus pitch, tinnitus loudness, and residual inhibition. Participants completed the Visual Analog Scale (VAS) for tinnitus severity, the Tinnitus Handicap Inventory (THI), the Beck Depression Inventory (BDI), and the Beck Anxiety Inventory (BAI). Additionally, DTI was performed, and both fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were calculated from the inferior colliculus, Heschl’s gyrus, lateral geniculate body, and lateral lemniscus regions. Participants received tVNS treatment with the Vagustim TENS device for 10 sessions (each 30 min long). Initial assessments were repeated after treatment. After two weeks of tVNS treatment, significant improvement was observed in BDI and THI scores in individuals with subjective chronic tinnitus (p = 0.047 and p = 0.007, respectively). Furthermore, a significant decrease was observed in the FA values of the inferior colliculus (p = 0.001). However, no significant changes were detected in BAI scores, VAS, tinnitus pitch, tinnitus loudness, and residual inhibition (p > 0.05). The findings suggest that tVNS has potential benefit in reducing the daily burden of tinnitus and depression levels, and the effects of tinnitus on central auditory pathways may be modulated through neuroplastic changes. The results suggest that DTI can be utilized to assess the outcomes of tinnitus treatment. However, due to the small sample size and the absence of a control group, these results should be interpreted with caution. Further research is needed in this area.