Comparing the match-to-target for initial-fit and REM, for Phonak hearing aids fitted to adults via NHS

Abstract

Objective: The aim of this study was to compare the deviation from NAL-NL2 prescription targets using: Phonak’s manufacturer software-based initial-fit, real ear measurement REM, and real-ear measurements adjustment based on participant request REM +Adj. Design: A retrospective analysis comparing the initial fit and REMs for Phonak hearing aids fitted to adults through the National Health Service. Sample: A total of 255 participants visited one adult hearing aid service provided by the UK NHS at the Royal Surrey County Hospital's audiology clinic between April 2021 and January 2023. The study’s dataset comprised 457 ears, predominantly fitted with Phonak Behind-The-Ear (BTE) hearing aids, constituting 99.78% of the sample. Results: At a 65 dB Sound Pressure Level (SPL) input level, Phonak hearing aids demonstrated accuracy in matching the NAL-NL2 targets across the manufacturer software-based initial fit, REM, and REM +Adj methods. Notably, the initial fit approach registered a median root mean squared error (RMSE) of 4.8 (IQR = 2.7), while both REM and REM Adj approaches recorded a median RMSE of 3.0 (IQR = 2.6). Conclusions: The study’s findings indicate that Phonak hearing aids, when fitted using both initial fit and REM methodologies, demonstrate a close correspondence with the NAL-NL2 prescription target. The generalizability of these results to other hearing aid models remains to be explored.