Virtual Auditory Space Training-Induced Changes of Auditory Spatial Processing in Listeners with Normal Hearing

Abstract

OBJECTIVE:Localization involves processing of subtle yet highly enriched monaural and binaural spatial cues. Remediation programs aimed at resolving spatial deficits are surprisingly scanty in literature. The present study is designed to explore the changes that occur in the spatial performance of normal-hearing listeners before and after subjecting them to virtual acoustic space (VAS) training paradigm using behavioral and electrophysiological measures. MATERIALS and METHODS:Ten normal-hearing listeners participated in the study, which was conducted in three phases, including a pre-training, training, and post-training phase. At the pre-and post-training phases both behavioral measures of spatial acuity and electrophysiological P300 were administered. The spatial acuity of the participants in the free field and closed field were measured apart from quantifying their binaural processing abilities. The training phase consisted of 5-8 sessions (20 min each) carried out using a hierarchy of graded VAS stimuli. RESULTS:The results obtained from descriptive statistics were indicative of an improvement in all the spatial acuity measures in the post-training phase. Statistically, significant changes were noted in interaural time difference (ITD) and virtual acoustic space identification scores measured in the post-training phase. Effect sizes (r) for all of these measures were substantially large, indicating the clinical relevance of these measures in documenting the impact of training. However, the same was not reflected in P300. CONCLUSION:The training protocol used in the present study on a preliminary basis proves to be effective in normal-hearing listeners, and its implications can be extended to other clinical population as well.

Differential advantages of musical backgrounds on binaural integration and interaction skills in instrumentalists, vocalists, and non-musicians

“…After the preliminary inclusion tests, all the participants (group 1, group 2, and group 3) of the study underwent a battery of auditory tests targeting two binaural processing abilities: Binaural integration (DST and VASI) and binaural interaction (ITD and ILD). While DST, ITD, and ILD were conducted using the psychoacoustic toolbox in MATLAB version 2019b software (Mathworks, Natick, Massachusetts, USA) and the VASI test ( Nisha & Kumar, 2017 ) was administered using Paradigm Player ( Paradigm Stimulus, 2016 ).…”

“…The VASI test used is adapted from the study by Nisha and Kumar (2017) . Following familiarisation with the stimuli and task, the VASI test was conducted.…”

“…The importance of these cues for spatial hearing has been addressed by the duplex hypothesis, which claims that the localization of auditory stimuli is caused by two distinct mechanisms, the first uses information about ITDs which operates at low frequencies and the second uses information about ILDs that predominate at high frequencies ( Blauert, 1997 ). Another important cue for spatial hearing is the spectral cues of the pinna, which can be analysed by virtually synthesized stimuli ( Nisha & Kumar, 2017 ). Musicians have been reported to have better binaural perception (ITD thresholds, ILD thresholds, virtual auditory space identification - VASI scores and subjective ratings) when compared to non-musicians ( Nisha et al., 2022 ).…”

Comparison of a Free-Field and a Closed-Field Sound Source Identification Paradigms in Assessing Spatial Acuity in Adults With Normal Hearing Sensitivity

“…Irving and Moore [10] presented broadband noise bursts from an array of 24 speakers spaced equally, spanning the 360° horizontal plane, to assess spatial acuity in normal-hearing adults fitted with a unilateral earplug. Another study assessed spatial acuity in a sound field with 18 speakers arranged in a circle with a radius of 1 m [12].…”

“…More recently, Nisha and Kumar [12] developed the virtual auditory space identification (VASI) test to assess spatial acuity using virtual sources in a closed field. It involved presenting sounds from eight different virtual spatial locations (0°, +/-45°, +/-90°, +/-135°, 180°) and assessing the spatial acuity.…”