Spatial release from masking assessment in virtual reality for bilateral cochlear implants users

In addition to enhanced sound localisation abilities, one of the potential benefits of having bilateral cochlear implants is the improvement of speech-in-noise perception, as bilateral auditory inputs potentially allow the spatial separation of speech and noise sources. This process is known as spatial release from masking (SRM). When assisting bilateral cochlear implant users, it is essential to assess binaural hearing performance in a timeefficient manner, trying to maintain some of the real-world complexities, e.g. multiple sources and reverberation. Traditional tests of SRM and/or localization are often time consuming, and typically assess these in unrealistic settings, with only one controlled stimulus to attend to. With this in mind, Bizley and colleagues (2015) developed the Spatial Speech in Noise test (SSiN), which allows for the simultaneous evaluation of speech discrimination for various locations, SRM, and relative localisation measures using speech in a background babble. Within the BEARs (Both EARs) project, we have recently developed a Virtual Reality-based binaural training applications suite aimed at improving spatial hearing, speech-in-noise perception and ease of listening for bilateral cochlear implantees. In order to assess the impact of training on SRM and localisation without requiring custom spaces and expensive loudspeakers arrays, we have developed a 3D headphones-based implementation of the SSiN test. This article includes details of this implementation