(0974) Virtual Reality as a Method to Study Head Movements During Sound Localization Tasks

Introduction: Head movements improve sound localization in individuals with normal hearing (NH) and hearing loss (HL), however, there are no studies quantifying the nature of those head movements. We propose an accessible method, virtual reality (VR), to measure head movement kinetics during sound localization tasks in NH individuals with intent to use this system for future studies with HL individuals.

Methods: IRB was obtained. NH individuals (n=9) were recruited and underwent a screening audiogram to verify hearing status. A Speech, Spatial, and Qualities of Hearing (SSQ) questionnaire was given. Three 360o VR environments were developed using MetaQuest (Meta, CA) and Unity (Unity Technologies, CA) testing an individual’s ability to find 1) 8 visual targets, 2) 16 sound targets without visual targets, and 3) 32 sound targets with simultaneous visual targets. Experiments were conducted in the same order for a total of 56 trials. Root mean squared error (RMSE), statistical analysis, and head movement kinematic analysis were performed using MATLAB (MathWorks, MA).

Results: Participant’s mean SSQ=8.5 (range 7-9.3). Our VR environment #3 mean RMSE=14.6o was comparable to similar work (Coudert 2021, VR environment with 4 sound sources and NH subjects with mean SSQ=7.2 and RMSE=16.2o). We analyzed Euler Y head movements in #3 environment with the mean path distance=293.6o, peak velocity=192.4o/sec, latency=6.5 sec, number of head adjustments=2.3, and head movement complexity (polynomial fit order with error less than < 35)=2.0 (std = 150.8o, 69.9o/sec, 5.4 sec, 1.5, 1.1, respectively).

Conclusions: Our VR environment’s comparable RMSE indicates this VR environment produces results consistent with prior work. Our additional head movement measurements demonstrate this method can detect variations in head movement patterns. This method will allow 1) quantification of head movements and their potential role in different sound localization abilities in those with aided and unaided HL and 2) studies on therapeutic benefit of accessible VR head movement training for individuals with reduced sound localization ability.