Venting corrections improve the accuracy of coupler-based simulated real-ear verification for use with adult hearing aid fittings

Background: Hearing aid responses can be verified with the Real Ear Aided Response (REAR). Procedures for predicting the REAR from coupler-based verification exist, but have not incorporated corrections for venting, limiting their use and validity for vented and open fittings. A commercially-available system for including venting effects in simulated real-ear measurement (S-REM) has recently been developed. Purpose: To evaluate the accuracy of a vent-corrected S-REM for predicting the REAR across test levels, for fittings with a wide range of coupling styles including modular domes. Research design: This was a within-subjects comparison study using technical measures. Retrospective file review was used to obtain previously-measured REARs from 104 fittings in 52 adults and three hearing aid styles. Prospective data collection was used to re-measure each fitting at three test levels using S-REM with and without venting corrections. Comparison of differences by frequency band were performed to assess the impact of the venting correction. Results: The vent model reduced low-frequency error by up to 11 dB, and the effects were consistent with the expected effects of venting in hearing aid fitting: fittings with more open dome or tip styles had a larger improvement when the vent model was added. A larger sample of fittings was obtained for dome/sleeve couplings than for custom fittings. Conclusions: The vent-corrected S-REM system evaluated in this study provides improved fitting accuracy for dome or sleeve-fitted hearing aids for adults and supports the use of vented S-REM for open fittings. Further study to examine a representative sample of custom tip or mold fittings, and fittings for children are future directions.