Patients with unilateral tinnitus: evaluation of high-frequency audiometry and ABR results

Aim This study aimed to investigate the pathology of tinnitus by analyzing Auditory Brainstem Response (ABR) waves and Extended High-Frequency Audiometry (EHFA) in patients with unilateral tinnitus without clinically detectable hearing loss. Methods In a retrospective case-control study, data from 48 patients with unilateral tinnitus were divided into two groups: ears with tinnitus and ears without tinnitus. ABR test results and EHFA test results were compared. The ABR test was applied in two different protocols, and the results were compared. Results Significant differences were observed in ABR wave latencies and amplitudes between ears with and without tinnitus. Specifically, the latency of the wave I was prolonged, and the wave III and V amplitudes were reduced in ears with tinnitus. EHFA results showed a higher number of ears exceeding the hearing threshold in tinnitus ears, although no significant difference was observed between ears with and without tinnitus. A comparison of ABR results across stimulus repetition rates revealed significant differences in most parameters. Conclusion The study emphasizes that distal pathologies of the 8th nerve should be investigated, and that changes in ABR latencies despite normal hearing thresholds should be considered in light of possible future degeneration. It also recommends specifying ABR stimulus repetition rates in research and applying EHFA in patients with unilateral tinnitus complaints to comprehensively assess tinnitus pathology.