Monitoring Hearing Function in Patients With Sporadic Vestibular Schwannoma: A Feasibility Study to Inform a Future Randomized Controlled Trial

OBJECTIVE: There is a need for a definitive RCT comparing upfront stereotactic radiosurgery (SRS) versus watch-and-wait (WW) for long-term hearing preservation in vestibular schwannoma (VS). Specific objectives of this feasibility study were to: (1) assess patient eligibility and recruitment/ retention rates, (2) determine completion rates/ times, and (3) estimate the variance in key proposed outcome measures to inform sample-size estimation for an RCT. STUDY DESIGN: Nonrandomized, single-centre, prospective study. SETTING: Tertiary-referral centre. PATIENTS: Thirty-one patients with sporadic VS undergoing WW (n = 22) or SRS (n = 9). INTERVENTIONS: Four-frequency average pure-tone audiometry (4FAPTA) thresholds, Word Recognition Scores (WRS), monaural/antiphasic Digits-in-Noise speech reception thresholds (DiN SRT50), and self-reported outcomes including the Speech, Spatial and Qualities of Hearing Scale (SSQ) and Tinnitus Functional Index (TFI). MAIN OUTCOME MEASURES: Feasibility metrics (recruitment, completion rates, testing times). Variance of outcome measures (hearing-related: 4FAPTA, monoaural/ antiphasic DiN-SRT50, WRS. Patient-reported outcomes: SSQ, TFI. RESULTS: Forty-four patients were recruited over 7 months. Thirty-one (70.5%) met inclusion criteria, and 25 (80%) completed all tests. Average time to complete the assessments was 1 hour 42 minutes. Mean 4FAPTA (±SD) in VS-affected ears was 42 ± 14 dB HL (WW) and 55 ± 9.4 dB HL (SRS). Antiphasic DiN-SRT50 thresholds were WW: -14.2 dB SNR ± 4.1; SRS: -11.6 dB SNR ± 1.9, and 4FAPTA and antiphasic DiN-SRT50 were correlated (P < 0.001) in VS-affected ears. CONCLUSIONS: This study has demonstrated sufficient eligibility and recruitment/retention rates for the proposed RCT and high-test completion rates with acceptable duration. Variability estimates of key outcome measures (DiN-SRT50, 4FAPTA) have also been provided to determine the sample size for the RCT.