Visual feedback to improve the accessibility of head-mounted displays for persons with balance impairments

Abstract

The objective of this research is to improve the accessibility of Head-Mounted Displays (HMDs) for users with balance impairments while they are in immersive Virtual Environments (VEs). Previous research has shown that most users experience some imbalance in a fully immersive VE (i.e., wearing a HMD that blocks the user's view of the real world). However, this imbalance is significantly worse in users with balance deficits. Persons with balance impairments often depend more on visual feedback than persons without impairment to maintain their balance. Thus, this research aims to determine an effective visual feedback technique to improve balance of persons while using VEs to improve the accessibility of HMDs. In order to do that, we conducted a study with seven users without impairment and seven users with balance impairments due to Multiple Sclerosis (MS). In the study, each user wore a tracked head-mounted display while they played a balance game in which they had to dodge a series of virtual tennis balls thrown at them while standing on a Wii balance board. We investigated how a static rest frame (SRF) (e.g., a cross-hair always rendered in the same position on the user's display screen) impacts the participants' balances in VR. Results indicate that a SRF significantly improves balance in VR for users with MS. Based on these results, we propose guidelines for designing more accessible VEs for persons with balance impairments.