Early hearing improvement predicts complete recovery in sudden hearing loss.
TL;DR
Early hearing improvement within two weeks is a readily obtainable and quantitatively informative predictor of complete recovery in SSNHL and its prognostic value is greatest in patients with less severe pretreatment hearing loss and diminishes with increasing hearing severity.
Abstract
Background
Early prediction of recovery in sudden sensorineural hearing loss (SSNHL) remains challenging. Early hearing improvement (EHI) may serve as a simple prognostic marker, but its quantitative relationship with complete recovery (CR) has not been well defined. We investigated the association between EHI and CR and explored whether this relationship differed according to pretreatment hearing severity.
Methods
We conducted a retrospective case-control study of adults hospitalized for a first episode of unilateral SSNHL at a tertiary referral center in Taiwan between 2012 and 2022. Patients who achieved CR, defined as a final four-frequency pure-tone average ≤25 dB HL, were matched by pretreatment hearing grade to patients without CR. EHI was defined as the change in pure-tone average from baseline to the first follow-up audiogram within two weeks. Multivariable linear probability models and logistic regression were used to evaluate the association between EHI and CR.
Results
The study included 240 patients (120 with CR and 120 without CR). Younger age and a shorter onset-to-treatment interval were independently associated with a higher probability of CR (age: β per 1-year increase, -0.009; 95% CI, -0.013 to -0.005; p < 0.001; onset-to-treatment interval: β per 1-day increase, -0.013; 95% CI, -0.018 to -0.009; p < 0.001). Mean EHI was 14.9 ± 19.1 dB and increased with pretreatment hearing grade. Each 1-dB increase in EHI was associated with a 1.5% higher probability of CR (β = 0.015, 95% CI 0.012-0.017; p < 0.001). The strength of this association progressively decreased as pretreatment hearing severity increased. Findings were consistent in sensitivity analyses using logistic regression.
Conclusion
Early hearing improvement within two weeks is a readily obtainable and quantitatively informative predictor of complete recovery in SSNHL. Its prognostic value is greatest in patients with less severe pretreatment hearing loss and diminishes with increasing hearing severity.