Effects of Stimulation Position and Frequency Band on Auditory Spatial Perception with Bilateral Bone Conduction

Abstract

Virtual sound localization tests were conducted to examine the effects of stimulation position (mastoid, condyle, supra-auricular, temple, and bone-anchored hearing aid implant position) and frequency band (low frequency, high frequency, and broadband) on bone-conduction (BC) horizontal localization. Non-individualized head-related transfer functions were used to reproduce virtual sound through bilateral BC transducers. Subjective experiments showed that stimulation at the mastoid gave the best performance while the temple gave the worst performance in localization. Stimulation at the mastoid and condyle did not differ significantly from that using air-conduction (AC) headphones in localization accuracy. However, binaural reproduction at all BC stimulation positions led to similar levels of front-back confusion (FBC), which were also comparable to that with AC headphones. Binaural BC reproduction with high-frequency stimulation led to significantly higher localization accuracy than with low-frequency stimulation. When transcranial attenuation (TA) was measured, the attenuation became larger at the condyle and mastoid, and increased at high frequencies. The experiments imply that larger TAs may improve localization accuracy but do not improve FBC. The present study indicates that the BC stimulation at the mastoid and condyle can effectively convey spatial information, especially with high-frequency stimulation.

Evaluating binaural hearing capabilities in individuals with sensorineural hearing loss through bilateral bone conduction stimulation

“…However, these differences were not statistically signi cant, suggesting that the improved speech perception in both the unilateral and bilateral conditions in the asymmetric group, and with BC stimulation in the symmetric group, can be attributed solely to the head shadow of the noise, or the better ear effect. This nding is supported by a recent study where the speech stimulation was at one ear and the noise position varied between co-located and at the opposite ear 29 . In that study, when the noise position was at the contralateral side, the head shadow dominated the mechanism for spatial bene t.…”

Auditory localization: a comprehensive practical review

“…This perceptual confusion is particularly common when synthetic sounds are played or audio headphones are used (i.e., in particular when non-individualized HRTFs are used) ( Begault et al, 2001 ; Rychtáriková et al, 2011 ). It is particularly critical when bone-conduction audio headphones are used since these, by exploiting an alternative communication channel to the inner ear, completely bypass the outer ear and its contribution to spatial perception ( Wang et al, 2022 ). One way to reduce front-back confusion could be to introduce reverberations in synthesized signals.…”