Virtual reality sound localization testing in cochlear implant users

Abstract

Localizing sounds in our environment is a fundamental perceptual ability. However, methods to assess sound localization ability are often cumbersome, requiring large speaker array systems. In adults with sensorineural hearing loss who are fitted with cochlear implant (CIs), sound localization is known to improve when bilateral CIs are used compared to a single CI. This study proposes a portable virtual reality (VR) tool for measuring sound localization in bilateral cochlear implant (CI) users. Head related transfer functions (HRTFs) were used to replicate 3-dimensional sounds delivered to the users via headphones or a direct connect (DC) CI audio cable. Users wearing the VR headset were then instructed to turn and face these sound sources. From measurements of head position and velocity, objective measures of accuracy were derived. Pilot testing of the device was conducted with 4 bilateral CI participants and 12 normal hearing (NH) participants. Results showed that NH listeners performed better than CI users in all metrics. Bilateral CI users performed above chance level when presented with sounds to their first implanted ear only or to both implants simultaneously. Compared to previously reported localization studies, NH listeners demonstrated lower performance using this VR system. This study provides a foundation for objective sound localization testing in bilateral CI users in a clinical setting.