Characteristics and Spontaneous Recovery of Tinnitus Related to Idiopathic Sudden Sensorineural Hearing Loss

OBJECTIVE To evaluate the characteristics and spontaneous recovery of tinnitus related to idiopathic sudden sensorineural hearing loss (ISSNHL). STUDY DESIGN Retrospective analysis from two randomized placebo-controlled clinical trials for treatment of ISSNHL within 48 hours from onset (Study A), or of tinnitus related to ISSNHL within 3 months from onset (Study B). SETTING Forty-eight European sites (academic tertiary referral centers, private ENT practices). PATIENTS One hundred thirteen adult patients of which 65 with hearing loss ≥30 dB (Study A) and 48 with persistent acute tinnitus (Study B) at baseline. INTERVENTIONS Intratympanic (i.t.) injection of placebo gel in single dose or in triple dose during 3 consecutive days. MAIN OUTCOME MEASURES Frequency of tinnitus, subjective tinnitus loudness, rates of complete tinnitus remission, and complete hearing recovery during 3 months follow-up. RESULTS In acute ISSNHL, tinnitus loudness decreased rapidly in cases of mild-moderate hearing loss, and tinnitus had completely resolved in two-thirds of patients after 3 months. Hearing recovery preceded tinnitus resolution. When associated with severe-profound hearing loss, tinnitus improved significantly less. Complete hearing recovery and full tinnitus remission were both about three times more frequent in mild-moderate hearing loss patients than in severe-profound cases. Improvement in tinnitus loudness over time can be approximated by a negative exponential function. CONCLUSIONS Prognosis for ISSNHL-related tinnitus is relatively poor in case of severe-profound hearing loss and the longer it has persisted. Alleviation or management of tinnitus should be a key therapeutic objective especially in pronounced ISSNHL cases.