Perception of Auditory Distance in Normal-Hearing and Moderate-to-Profound Hearing-Impaired Listeners

Abstract

The auditory system allows the estimation of the distance to sound-emitting objects using multiple spatial cues. In virtual acoustics over headphones, a prerequisite to render auditory distance impression is sound externalization, which denotes the perception of synthesized stimuli outside of the head. Prior studies have found that listeners with mild-to-moderate hearing loss are able to perceive auditory distance and are sensitive to externalization. However, this ability may be degraded by certain factors, such as non-linear amplification in hearing aids or the use of a remote wireless microphone. In this study, 10 normal-hearing and 20 moderate-to-profound hearing-impaired listeners were instructed to estimate the distance of stimuli processed with different methods yielding various perceived auditory distances in the vicinity of the listeners. Two different configurations of non-linear amplification were implemented, and a novel feature aiming to restore a sense of distance in wireless microphone systems was tested. The results showed that the hearing-impaired listeners, even those with a profound hearing loss, were able to discriminate nearby and far sounds that were equalized in level. Their perception of auditory distance was however more contracted than in normal-hearing listeners. Non-linear amplification was found to distort the original spatial cues, but no adverse effect on the ratings of auditory distance was evident. Finally, it was shown that the novel feature was successful in allowing the hearing-impaired participants to perceive externalized sounds with wireless microphone systems.

Sound Externalization: A Review of Recent Research

“…Finally, it is worth mentioning several recent studies that have explored methods for adding realistic externalization cues (via HRTFs and room reverberation) to hearing-aid signals that would otherwise be internalized ( Courtois et al., 2019 ; Kates et al., 2018 , 2019 ). This line of work demonstrates the importance that hearing-aid wearers and hearing-aid manufacturers place on natural, externalized sound images.…”

Action planning and affective states within the auditory peripersonal space

“…Moreover, NH compared to CI individuals located the sounds within a significantly larger spatial range for positive and negative sounds (the range was defined by the closer and the farther points of localization). This might be caused by the reduced abilities of CI hearing system in discriminating sound intensities and frequencies both highly relevant for distance estimations (Brungart 1999;Courtois et al 2019;Kopčo and Shinn-Cunningham 2011;Zahorik 2002). Interestingly though for the neutral sound both NH and CI selected the same range.…”

Effects of Head-Tracking Artefacts on Externalization and Localization in Azimuth With Binaural Wearable Devices

“…A similar scale was used to rate externalization in [26]. This method was preferred over categorical scales such as the ones used in [3,4,27], or scales with visual references used in auditory distance estimation experiments [28] as no auditory or visual reference was available to the listener. Moreover, the design of the experiment did not allow to use MUSHRA-style interface or paired comparisons, as it would require too much memory effort for the listener to remember accurately the perceived externalization of the previous stimuli after completing the movement of the next ones.…”