Improving speech intelligibility in hearing aids. Part II: Quality assessment

Abstract

[EN] Subjective tests are the most reliable methods for quantifying the perceived speech intelligibility, but the process to perform these tests usually is time consuming and cost expensive. For this reason, different objective measures have been proposed in the literature to evaluate the intelligibility and/or quality of speech in such a way that cooperation of human listeners is not necessary. In this paper, we describe a wide range of subjective tests reported in the literature, focusing on those proposed to evaluate speech intelligibility of Spanish language, not only for normal hearing listeners, but for hearing impaired as well. Afterwards we summarize the most common objective measures of speech quality, and finally we perform a comparison between them and some subjective speech intelligibility tests. In the subjective tests, clean Spanish speech material has been contaminated with different real background noises: cafeteria and outside traffic noise. Results show that Short-Time Objective Intelligibility (STOI) and Perceptual Evaluation of Speech Quality (PESQ) indices present a better correlation and a lower mean square error when predicting intelligibility compared to other objective measures tested.