Rate of Initial Hearing Loss During Early Observation Predicts Time to Non-Serviceable Hearing in Patients With Conservatively Managed Sporadic Vestibular Schwannoma.

Abstract

To date, prediction models for estimating risk of acquiring non-serviceable hearing in subjects with observed vestibular schwannoma (VS) have evaluated outcomes primarily based on features at initial diagnosis. Herein, we evaluate the association of rate of hearing decline during the initial period of observation with time to non-serviceable hearing. If significant, rate of hearing decline may inform decision making after an introductory period of observation. Two tertiary care centers. VS patients with serviceable hearing who underwent at least three audiograms and two magnetic resonance imaging (MRI) studies before intervention or being lost to follow-up. The rate of change in pure-tone average (PTA) and word recognition score (WRS) was calculated as the score from the second audiogram minus the score from the first audiogram, divided by the duration in months between the two. Serviceable hearing, defined as PTA ≤50 dB HL and WRS ≥50%. Among 266 patients meeting inclusion criteria, 52 developed non-serviceable hearing at last follow-up. Kaplan-Meier estimated rates of maintaining serviceable hearing (95% CI; number still at risk) at 1, 3, 5, 7, and 10 years were 97% (95-100; 206), 78% (72-85; 98), 68% (60-77; 39), 60% (50-73; 17), and 44% (29-67; 2), respectively. In a univariable setting, each 1 dB increase per month in the rate of initial PTA change was associated with a 96% increased likelihood of acquiring non-serviceable hearing (hazard ratio [HR] 1.96; 95% CI 1.44-2.68; p < 0.001). Each 1% increase per month in the rate of initial WRS change was associated with a decreased likelihood of acquiring non-serviceable hearing (hazard ratio [HR] 0.79; 95% confidence interval [CI] 0.66-0.94; p = 0.009). After multivariable adjustment, both rate of PTA change (HR 2.42; 95% CI 1.72-3.41; p < 0.001) and rate of WRS change (HR 0.81; 95% CI 0.67-0.99; p = 0.043) remained statistically significantly associated with time to non-serviceable hearing. Rate of early PTA and WRS decline during the initial period of observation are significantly associated with time to development of non-serviceable hearing. This information may facilitate accurate patient counseling and inform decision-making regarding prospective disease management.