NONSURGICAL FACTORS PREDICTIVE OF POSTOPERATIVE HEARING FOR PATIENTS WITH VESTIBULAR SCHWANNOMA

Objective: The purposes of the study were to determine whether preoper ative cochlear reserve as measured by evoked otoacoustic emissions (EO AE) as well as other hearing variables often associated with hearing p reservation are correlated with hearing preservation after tumor remov al and to determine whether any hearing variables are independent of t umor size as a predictor of hearing preservation. Study Design: Preope rative audiologic data for 104 patients having vestibular nerve schwan nomas removed via a retrosigmold surgical approach were reviewed and s ubjected to factor analysis. Setting: All patients were seen at the Ma yo Clinic, Rochester, Minnesota. Patients: The patient sample was divi ded into two groups based on hearing thresholds after surgery Group I consisted of 73 ears without hearing preservation. The remaining 31 ea rs, group II, had preserved hearing (defined as average postoperative pun-tone thresholds less than or equal to 85-dB HL for 0.5, 1, 2, and 3 kHz). Main Outcome Measures: Variables not predictive of hearing pre servation were age, gender, tumor laterality, and cochlear reserve (EO AE). Variables predictive of hearing preservation were small tumor siz e, pure-tone hearing sensitivity, speech reception thresholds, word re cognition scores, integrity of cochlear nerve (acoustic reflex thresho lds, and auditory brain stem response [ABR] waveforms). Results: A mul tivariate logistic regression analysis showed that only word recogniti on scores at 40-dB sensation level were independent of tumor size as a predictor of hearing preservation.