Ginkgo biloba Extract EGb 761^® in Patients with Chronic Tinnitus: Treatment Effects and Effect Modifiers

Background/Objectives: An exploratory study was conducted to investigate the effect of Ginkgo biloba extract EGb 761^® in the management of chronic tinnitus, and whether comorbidities have an impact on the treatment outcome. Methods: The exploratory, uncontrolled, open-label study enrolled 170 patients (Full Analysis Set) with chronic tinnitus who took 120 mg EGb 761^® twice daily for 24 weeks. Outcomes were assessed using the Tinnitus Questionnaire, Tinnitus Handicap Inventory, and 11-Point Box Scales for loudness and annoyance. Comorbidities were recorded with audiometry, the Hospital Anxiety and Depression Scale, and the Perceived Stress Questionnaire. The effectiveness was further examined in responder analyses (at least 30% score reduction in 3 out of 4 outcomes) and in subgroups defined by baseline anxiety, hearing impairment, stress and depression. Results: At week 24, significant improvements were observed in all tinnitus-related outcomes compared to baseline (all p < 0.0001). In subgroup analyses, patients with high baseline anxiety or stress as well as those with normacusis improved more, whereas baseline depression had no influence. The overall response rate was 18.8%. Conclusions: The results of this exploratory study indicate that EGb 761^® improved complaints in patients with chronic tinnitus. The therapy appears to be particularly beneficial for patients with normal hearing and/or concomitant anxiety and/or stress. Trial registration: The study was registered at ISRCTN (ISRCTN83863387, registration date 14 October 2016).