Evidence of Cochlear Synaptopathy and the Effect of Systemic Steroid in Acute Idiopathic Tinnitus with Normal Hearing.

Objective To evaluate the electrophysiologic evidence of cochlear synaptopathy and the effects of systemic steroids in acute idiopathic tinnitus with normal hearing. Study design Retrospective review of medical data. Setting Tertiary referral center. Patients Fifty-nine patients who experienced acute-onset idiopathic tinnitus (within 12 weeks) with normal hearing and the same number of age- and pure-tone threshold-matched control groups. Intervention Electrophysiologic studies of the auditory pathway, oral steroids, and ginkgo biloba. Main outcome measures Pure-tone thresholds, wave I and wave V amplitudes of the auditory brainstem response (ABR), tinnitus handicap inventory (THI), and visual analog scale (VAS). Results Significantly reduced ABR wave I amplitude and wave I/wave V ratio were found in the tinnitus group compared with the no tinnitus group. Age and pure-tone threshold were significantly correlated with reduced wave I amplitude and small wave I/wave V ratio. The THI and VAS scores were decreased at 3 and 12 weeks after steroid administration; however, overall changes in THI and VAS scores were not significantly different between the steroid and ginkgo biloba groups. Conclusion Potential cochlear synaptopathy was suspected in the early stage of acute idiopathic tinnitus, even in patients with normal hearing. Age and hearing threshold were potentially associated with the development of cochlear synaptopathy. Low-dose oral steroids and ginkgo biloba induced early subjective relief of tinnitus, which maintained up to 12 weeks, however, those changes did not differ between groups.