The effect of hearing aid dynamic range compression on speech intelligibility in a realistic virtual sound environment

Measures of "aided"speech intelligibility (SI) for listeners wearing hearing aids (HAs) are commonly obtained using rather artificial acoustic stimuli and spatial configurations compared to those encountered in everyday complex listening scenarios. In the present study, the effect of hearing aid dynamic range compression (DRC) on SI was investigated in simulated real-world acoustic conditions.

A spatialized version of the Danish Hearing In Noise Test was employed inside a loudspeaker-based virtual sound environment to present spatialized target speech in background noise consisting of either spatial recordings of two real-world sound scenarios or quadraphonic, artificial speech-shaped noise (SSN).

Unaided performance was compared with results obtained with a basic HA simulator employing fast-acting DRC. Speech reception thresholds (SRTs) with and without DRC were found to be significantly higher in the conditions with real-world background noise than in the condition with artificial SSN. Improvements in SRTs caused by the HA were only significant in conditions with real-world background noise and were related to differences in the output signal-to-noise ratio of the HA signal processing between the real-world versus artificial conditions.

The results may be valuable for the design, development, and evaluation of HA signal processing strategies in realistic, but controlled, acoustic settings.