Accounting for individual differences in the effects of hearing protectors on sound source localization

Abstract

Modern hearing protection devices (HPDs) mitigate the risk of noise-induced hearing loss when used as intended, but negative auditory perceptual side-effects continue to limit usability in critical settings. Dozens of studies, including previous studies by our group, have shown that HPDs lead to significant errors in sound source localization, including large errors in source elevation perception and disorienting front-back confusions. Degradation of performance relative to open-ear listening arises due to peripheral disruptions of monaural and binaural acoustic cues for sound localization; for higher-attenuation devices, reduced audibility can also limit access to these cues, even if cues are relatively intact. A recent multi-site effort by our group leveraged manikin-based acoustic measurements of HPD-induced signal distortions to predict human localization performance during HPD use. Manikin-based acoustic metrics were positively correlated with behavioral performance across a large population of human listeners (n ≥ 120), enabling discrimination of localization impacts across HPDs, but significant individual variability was evident. Here we consider individual factors that may contribute to variability in HPD localization impact across wearers, including audiometric factors and auricular/acoustic factors. Correlational analyses of individualized predictors with localization performance provide new insight on factors that may differentially constrain – or facilitate – sound localization during HPD use.