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

Background and objectives: Traditional sound field localization setups in a free-field environment closely represent real-world situations. However, they are costly and sophisticated, and it is difficult to replicate similar setups in every clinic. Hence, a cost-effective, portable, and less sophisticated virtual setup will be more feasible for assessing spatial acuity in the clinical setting. The virtual auditory space identification (VASI) test was developed to assess spatial acuity using virtual sources in a closed field. The present study compares the legitimacy of these two methods.

Subjects and methods: Fifty-five individuals with normal hearing (mean age±SD: 21± 3.26 years) underwent spatial acuity assessment using two paradigms: 1) the sound field paradigm (localization test) and 2) the virtual paradigm (VASI test). Location-specific and overall accuracy scores and error rates were calculated using confusion matrices for each participant in both paradigms.

Results: The results of Wilcoxon signed-rank tests showed that the locationspecific and overall accuracy scores for both paradigms were not significantly different. Further, both paradigms did not yield significantly different localization error rates like right and left intra-hemifield errors, inter-hemifield errors, and front-back errors. Spearman's correlation analysis showed that all the measures of the two paradigms had mild to moderate correlation.

Conclusions: These results demonstrate that both VASI and the sound field paradigm localization test performed equally well in assessing spatial acuity.