AUTHOR=Nisha Kavassery Venkateswaran , Uppunda Ajith Kumar , Kumar Rakesh Trinesh 

TITLE=Spatial rehabilitation using virtual auditory space training paradigm in individuals with sensorineural hearing impairment

JOURNAL=Frontiers in Neuroscience

VOLUME=Volume 16 - 2022

YEAR=2023

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2022.1080398

DOI=10.3389/fnins.2022.1080398

ISSN=1662-453X

ABSTRACT=The present study aimed to quantify the effects of spatial training using virtual sources on a battery of spatial acuity measures in listeners with sensorineural hearing impairment (SNHI). An intervention based time-series comparison design involving 82 participants divided into three groups was adopted. Group I (n = 27, SNHI-spatially trained) and group II (n = 25, SNHI-untrained) consisted of SNHI listeners while group III (n = 30) had listeners with normal hearing (NH). 
The study was conducted in three phases. At pre-training phase, all the participants underwent a comprehensive assessment of their spatial processing abilities using a battery of tests including spatial acuity in free-field and closed-field, tests for binaural processing abilities (interaural time and level difference thresholds – ITD & ILD) and, subjective ratings. While spatial acuity in the free field was assessed using a loudspeaker-based localization test, the closed-field source identification test was performed using virtual stimuli delivered through headphones. The ITD and ILD thresholds were calculated using MATLAB, while the participant ratings on the spatial subsection of speech, spatial, and qualities in Kannada were used for the subjective ratings. Group I listeners underwent virtual auditory spatial training (VAST), following pre-evaluation assessments. All tests were re-administered on group I listeners halfway through training (mid-training evaluation phase), and after training completion (post-training evaluation phase), whereas group II underwent these without any training at the same time intervals.
Statistical analysis showed main effect of groups in all tests at pre-training evaluation phase, with post-hoc comparisons that revealed group equivalency in spatial performance of both SNHI groups (group I and group II). Effect of VAST in group I was evident on all the tests, with localization test showing highest predictive power for capturing VAST related changes on Fischer discriminant analysis (FDA). In contrast, group II demonstrated no changes in spatial acuity across timelines of measurements. FDA also complimented revealed increased errors in categorization of NH as SNHI-trained at post-training evaluation compared to pre-training evaluation, as the spatial performance of the latter improved with VAST in post-training phase.