Comprehensive evaluation of binaural hearing aid pre-processing strategies—Speech intelligibility in realistic noise scenarios

• Published in: The Journal of the Acoustical Society of America 2016-04, Vol.139 (4), p.2043-2043
• Main Authors: Ernst, Stephan, Baumgärtel, Regina, Völker, Christoph, Warzybok, Anna, Dietz, Mathias, Hohmann, Volker, Kollmeier, Birger
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4950044

For the development of new signal processing approaches, e.g., for hearing aids, a final stage of evaluation is crucial. However, the evaluation procedures for assessing performance and benefit often represent a vast and not unified realm. Thus, we suggest a comprehensive evaluation to describe the efficacy, i.e., the anticipated real-world benefit as precise as possible. This comprises physical, instrumental, and perceptual (human) measurements of objective measures, as well as subjective attributes. Eight signal pre-processing strategies were evaluated following this concept, including directional microphones, coherence filters, single-channel noise reduction, binaural beamformers, and their combinations. Speech reception thresholds (SRTs) were measured with normal-hearing and hearing-impaired listeners in three realistic noise scenarios and compared with predictions of common instrumental measures. Although hearing-impaired listeners required a better signal-to-noise ratio to obtain 50% intelligibility than listeners with normal hearing, no differences in SRT benefit (of up to 4.8 dB) from the different algorithms were found between the two groups. This suggests a possible application of noise reduction schemes for listeners with different hearing status. Although the instrumental measures can predict the individual SRTs without pre-processing, development is necessary to predict the benefits obtained from the algorithms at an individual level.