Development of a test environment to evaluate performance of modern hearing aid features.

This article describes a new test environment and materials with the potential to measure performance differences among different hearing aid signal processing methods and features. Normative data suggest a linearly predictable increase in difficulty on a speech-in-noise task as the masker changes from random noise to multiple-talker speech, and the number of talkers increases. Data collected with normal listeners revealed no differences across four test sites for the single loudspeaker (Noise-Front) results and some differences across test sites for the multiple loudspeaker results. Room dimension differences among audiometric test enclosures and diffusion (or lack thereof) of the maskers in the vertical and horizontal dimensions of the sound fields appear to account for performance differences for the multiloudspeaker arrays, confirming the need to limit maskers to aperiodic signals in rooms with controlled ceiling height or to establish norms for each test environment such that results obtained in different enclosures can be compared.