The Effect of Electrical Stimulation Therapy on Brain Derived Neurotrophic Factor in Patients with Tinnitus

Introduction: The aim of this study was to determine the effect of electric stimulation therapy on brain-derived neurotrophic factor (BDNF) in patients with tinnitus. Materials and methods: In this before-after clinical trial study, 45 patients aged 30-80 years old with tinnitus were involved. The hearing threshold, loudness, and frequency of tinnitus were assessed. Tinnitus Handicap Inventory (THI) questionnaire was completed by the patients. Before holding electrical stimulation sessions, the patients were evaluated for serum brain-derived neurotrophic factor (BDNF) level. Patients underwent five electrical stimulation sessions of 20 min for 5 consecutive days. After completion of electrical stimulation session, THI questionnaire was re-completed by the patients and they were evaluated for serum BDNF level. Results: Mean BDNF level before and after the intervention was (1238 ± 494.2) and (1148.2 ± 496.7), respectively (P = 0.04). Mean loudness score before and after the intervention was (6.36 ± 1.47) and (5.27 ± 1.68), respectively (P = 0.01). Mean THI score before and after the intervention was (58.21 ± 11.8) and (53.17 ± 15.19), respectively (p = 0.01). In patients with severe THI1, there was a significant difference between serum BDNF level (p = 0.019) and loudness (p = 0.003) before and after the intervention. However, in patients with mild, moderate, and very severe THI1, no such effect was observed (p > 0.05). Conclusion: According to the results of the present study, electrical stimulation therapy significantly decreased the mean plasma BDNF level in patients with tinnitus, especially in patients with severe tinnitus so it can be used as a marker to define the response to treatment and determine the severity of tinnitus in primary evaluations.