Enhanced auditory spatial performance using individualized head-related transfer functions: An event-related potential study

Abstract

Head-related transfer functions (HRTFs) capture location dependent alterations to a sound caused by a physical interaction with a listener's head, shoulders, and outer ears. Sounds rendered with a listener's own HRTF can be localized with accuracy comparable to real sources; however, because anthropometric features vary across listeners, rendering sounds with non-individualized HRTFs can severely degrade localization of virtual sound source location, especially in elevation. Here, we were interested in identifying event-related potential (ERP) features associated with the benefit of employing individualized HRTFs. Thirty “runs” of 250 ms white-noise bursts (6–12 bursts long) with identical virtual elevations (0°–90°, 10° increments) were presented back-to-back within a block. Listeners were instructed to press a button whenever the elevation changed (i.e., at the start of each run). Elevation change detection was enhanced in an Individualized compared to a non-Individualized HRTF condition. ERPs to first bursts of a run showed larger amplitude P3s in the Individualized HRTF condition. Differences in P3 amplitudes between conditions were positively correlated with behavioral benefits gained from employing an individualized HRTF. That effects occurred for the P3 suggests that at least part of the benefit obtained from using individualized HRTFs reflects post-sensory processes.