Frequency-specific prediction model of hearing outcomes in patients with idiopathic sudden sensorineural hearing loss

Purpose The hearing outcome of idiopathic sudden sensorineural hearing loss (ISSNHL) is hard to predict. We herein constructed a multiple regression model for hearing outcomes in each frequency separately in an attempt to achieve practical prediction in ISSNHL. Methods We enrolled 235 consecutive in-patients with ISSNHL who were treated in our department from 2015 to 2020 (average hearing level at 250-4000 Hz >= 40 dB; time from onset to treatment <= 14 days; 126 males/109 females; age range 17-87 years (average 61.0 years)). All patients received systemic prednisolone administration combined with intratympanic dexamethasone injection. The pure-tone hearing threshold of 125-8000 Hz was measured at every octave before (HLpre) and after (HLpost) treatment. A multiple regression model was constructed for HLpost (dependent variable) using five explanatory variables (age, days from onset to treatment, presence of vertigo, HLpre, and hearing level of the contralateral ear). Results The multiple correlation coefficient increased as the frequency increased. Strong correlations were seen in high frequencies, with multiple correlation coefficients of 0.784/0.830 for 4000/8000 Hz. The width of the 70% prediction interval was narrower for 4000/8000 Hz (+/- 18.2/16.3 dB) than for low to mid-frequencies. Among the five explanatory variables, HLpre showed the largest partial correlation coefficient for any frequency. The partial correlation coefficient for HLpre increased as the frequency increased, which may partially explain the high multiple correlation coefficients for high frequencies. Conclusion The present model would be of practical use for predicting hearing outcomes in high frequencies in patients with ISSNHL.