Anna Warzybok1, Florian Kramer1, David Hülsmeier1, Birger Kollmeier1
1Medical Physics and Cluster of Excellence Hearing4all, Universität Oldenburg, Oldenburg, Germany
Precise methods in audiological diagnostics and understanding the impact of threshold and suprathreshold deficits on the audiological outcomes are crucial for the individualized and successful treatment with hearing devices. Model-based approaches may support the selection and fitting of hearing devices. This study aims at speech recognition and loudness perception of hearing-impaired listeners in acoustic conditions with increasing complexity, i.e., in well-controlled laboratory conditions like stationary masker in comparison to acoustically more complex and ecologically valid scenes like cafeteria ambience. Furthermore, in order to better understand the contribution of the individual loss in sensitivity and suprathreshold deficits to speech recognition subjective data are simulated with the framework of auditory discrimination experiments (FADE) considering different components of hearing impairment. For aided measurements, two prescription rules, pure-tone threshold-based NAL-NL2 and individual loudness perception-based trueLOUDNESS, are compared in terms of speech recognition and loudness perception. The outcomes of speech recognition measurements with hearing-impaired listeners show significant correlations of unaided speech recognition thresholds across the “simple” laboratory masking conditions. The performance in these conditions, however, show no significant correlation with performance in realistic cafeteria scenes. The benefit from hearing devices, defined as the difference in speech recognition threshold between the unaided and aided condition, differs across maskers and shows no correlation between laboratory and cafeteria maskers. While NAL-NL2 and trueLOUDNESS result in a comparable benefit in terms of speech recognition, the loudness perception is restored better with the trueLOUDNESS prescription rule. The accuracy of FADE simulations in unaided and aided conditions is highest when both components of hearing impairment (sensitivity loss and suprathreshold deficits) are accounted for. In summary, a model-based interpretation with a distinction between threshold and suprathreshold distortion component might not only be useful for diagnostic purposes but also helps to predict the benefit from a hearing device in acoustically challenging conditions.