Comparative Effectiveness of Sound Therapy, Transcranial Direct Current Stimulation, and Low-Level Laser Therapy for Chronic Tinnitus Management: A Randomized Clinical Trial

Background and Aim: Tinnitus, the perception of sound without an external source, can significantly impact the quality of life. Although no definitive cure exists, various treatments are available to reduce tinnitus symptoms. This study aimed to compare the effectiveness of sound therapy, trnscranial Direct Current Stimulation (tDCS), and Low-Level Laser Therapy (LLLT) in managing chronic tinnitus. Methods: In this randomized clinical trial, 78 adults with chronic tinnitus and normal hearing were divided into three groups of sound therapy, tDCS, and LLLT. The groups received interventions for six weeks. Psychoacoustically, we assessed tinnitus pitch, tinnitus loudness, Minimum Masking Level (MML), and residual inhibition (RI). Tinnitus loudness and distress were also measured using the Visual Analog Scales (VAS), and the functional impact was evaluated using the Tinnitus Handicap Inventory (THI) and Tinnitus Functional Index (TFI). Auditory Brainstem Response (ABR) test was performed to assess neural conduction. Results: All interventions significantly reduced tinnitus loudness, MML, and distress (p<0.05). Sound therapy showed the most significant improvements in THI, TFI, and VAS scores. No significant changes were found in ABR latencies. Post-hoc analysis revealed greater benefits in the sound therapy group regarding THI and TFI scores compared to the tDCS and LLLT groups. Conclusion: Sound therapy, tDCS, and LLLT are effective in reducing tinnitus symptoms, with sound therapy having greater effects. To improve procedures and investigate customized strategies, more research is recommended. IRCT registration number: IRCT20111113008082N5.