Improving User Performance in Haptics-Based Rehabilitation Exercises by Colocation of User's Visual and Motor Axes via a Three-Dimensional Augmented-Reality Display

Abstract

Serious games are recently becoming a common sight in rehabilitation settings to provide motivation for patients undergoing therapy to regain upper limb function after disability. These are often presented using a two-dimensional (2-D) monitor to the patient who uses a robotic device (haptic user interface) as the game controller. In this letter, we develop a 3-D spatial augmented reality (AR) display to colocate visual and haptic feedback to the user in three rehabilitative games. The same games are also displayed in a 2-D nonimmersive virtual reality (VR) and are compared against their AR counterpart in terms of user task performance to evaluate the benefit of the 3-D AR system. To simulate a rehabilitation scenario, able-bodied participants are put under cognitive load (CL) for simulating disability-induced cognitive deficiencies when performing the tasks. A within-subjects analysis of ten participants was carried out for the rehabilitative games. The results show that AR leads to the best user performance with or without cognitive loading. This result is most evident in dynamic exercises where the participants are required to have quick reaction times and fast movement. Furthermore, even while AR had a significant difference over VR, one of the tasks showed that the performance in AR between non-CL and CL cases was similar, thereby showing how AR can alleviate the negative effects of CL.