Assessment of feedback modalities for wearable visual aids in blind mobility

Sensory substitution devices engage sensory modalities other than vision to communicate information typically obtained through the sense of sight. In this paper, we examine the ability of subjects who are blind to follow simple verbal and vibrotactile commands that allow them to navigate a complex path. A total of eleven visually impaired subjects were enrolled in the study. Prototype systems were developed to deliver verbal and vibrotactile commands to allow an investigator to guide a subject through a course. Using this mode, subjects could follow commands easily and navigate significantly faster than with their cane alone (p <0.05). The feedback modes were similar with respect to the increased speed for course completion. Subjects rated usability of the feedback systems as "above average" with scores of 76.3 and 90.9 on the system usability scale.