Background: Tinnitus perception may be associated with impairments in the mechanisms of sensory gating (SG), which is a preattentive process that filters redundant auditory stimuli to prevent sensory overload. Acoustic stimulation of the auditory system alone (unimodal intervention), electrical stimulation of the vagus nerve alone, or a combination of both (bimodal intervention) can effectively treat tinnitus by influencing SG. Purpose: This study aimed to examine the impact of unimodal and bimodal interventions on auditory SG (ASG). Research Design: Participants were assigned to unimodal or bimodal intervention groups using block randomization after obtaining consent. Study Sample: Thirty-four participants with tonal tinnitus were divided equally into unimodal ( n 17) and bimodal ( n 17) groups. Intervention: Participants in the bimodal group received customized acoustic stimulation combined with transcutaneous auricular vagus nerve stimulation (tAVNS). Participants in the unimodal group received the same acoustic stimulation paired with sham tAVNS. Each group underwent six 20-minute treatment sessions. Data Collection and Analysis: Participants were assessed using the ASG (dividing the P1-N1 amplitude of the second cortical auditory evoked potential CAEP by the P1-N1 amplitude of the first CAEP) and an 11-point Visual Analog Scale (VAS) for loudness, awareness, and annoyance before and after the intervention sessions. Patients rated these items from 0 to 10, with 0 representing no tinnitus and 10 representing intense loudness, awareness, and annoyance. Postintervention group comparisons were performed using a covariance analysis. Within-group changes were assessed with paired t tests. Correlations were evaluated with Pearsons test. Results: After the intervention, the results showed that the bimodal group experienced a significant decrease in ASG and loudness and awareness VAS scores relative to those of the unimodal group (p 0.05). No significant change in the annoyance VAS score was found between groups. A correlation was observed between ASG and the awareness and annoyance VAS scores, but no correlation was found between ASG and the loudness VAS score. Conclusion: As a treatment option for tinnitus, bimodal stimulation appears to be more effective than unimodal stimulation. This method may be particularly beneficial for tonal tinnitus with hearing loss; however, it may not be effective for all patients. Therefore, a clinical protocol is required. Clinical Relevance Statement: Bimodal stimulation may offer a clinically meaningful intervention for patients with tinnitus, particularly those with hearing loss who experience tonal tinnitus.
Bolandi et al. (Thu,) studied this question.