Effect of immersive visualization technologies on cognitive load, motivation, usability, and embodiment

Abstract

Virtual reality (VR) is a promising tool to promote motor (re)learning in healthy users and brain-injured patients. However, in current VR-based motor training, movements of the users performed in a three-dimensional space are usually visualized on computer screens, televisions, or projection systems, which lack depth cues (2D screen), and thus, display information using only monocular depth cues. The reduced depth cues and the visuospatial transformation from the movements performed in a three-dimensional space to their two-dimensional indirect visualization on the 2D screen may add cognitive load, reducing VR usability, especially in users suffering from cognitive impairments. These 2D screens might further reduce the learning outcomes if they limit users’ motivation and embodiment, factors previously associated with better motor performance. The goal of this study was to evaluate the potential benefits of more immersive technologies using head-mounted displays (HMDs). As a first step towards potential clinical implementation, we ran an experiment with 20 healthy participants who simultaneously performed a 3D motor reaching and a cognitive counting task using: (1) (immersive) VR (IVR) HMD, (2) augmented reality (AR) HMD, and (3) computer screen (2D screen). In a previous analysis, we reported improved movement quality when movements were visualized with IVR than with a 2D screen. Here, we present results from the analysis of questionnaires to evaluate whether the visualization technology impacted users’ cognitive load, motivation, technology usability, and embodiment. Reports on cognitive load did not differ across visualization technologies. However, IVR was more motivating and usable than AR and the 2D screen. Both IVR and AR rea ched higher embodiment level than the 2D screen. Our results support our previous finding that IVR HMDs seem to be more suitable than the common 2D screens employed in VR-based therapy when training 3D movements. For AR, it is still unknown whether the absence of benefit over the 2D screen is due to the visualization technology per se or to technical limitations specific to the device.

Effects of Virtual Reality–Based Multimodal Audio-Tactile Cueing in Patients With Spatial Attention Deficits: Pilot Usability Study

“…The high usability of our new VR setting, including tactile stimulation, is similar to that in one of the few previous studies in stroke patients with a similar visual and auditory setting, which however did not entail any tactile stimulation [ 14 , 37 ]. Moreover, similar levels of usability have been reported by healthy participants using new VR tools including visual and auditory stimulation, but without tactile stimulation [ 36 , 50 , 51 ]. Hence, in our study, the additional presentation of tactile stimulation did not change usability or cause discomfort.…”

The relative contribution of five key perceptual cues and their interaction to the sense of embodiment.

“…Field of view, tactile feedback, and human likeness did not have a significant effect on task performance. The lack of an effect of field of view could be explained by the fact that even if it could affect the SoE, especially the sense of agency as reported in Wenk et al (2021), the reduction of this cue in the suppressive condition did not hamper task execution. This could also be related to both the design of the task, which was simple to accomplish, and the small workspace in which participants had to operate the virtual arm.…”

“…Normally, humans have a slightly over 210-degree forward-facing horizontal arc of their visual field, that is, without eye movements (with eye movements included it is slightly larger). It was demonstrated that a reduced field of view affects the sense of agency and can create movement impairments (Wenk et al, 2021).…”

“Tricking the Brain” Using Immersive Virtual Reality: Modifying the Self-Perception Over Embodied Avatar Influences Motor Cortical Excitability and Action Initiation

“…In this immersive virtual environment, the user interacts with a virtual self-representation perceived from first-person perspective (i.e., an avatar), realistically mimicking the body of the user. Previous work has suggested that immersive virtual reality, compared with screens, may further promote motor training because they enhance embodiment over the avatar ( Wenk et al, 2021 ) i.e., the body of the avatar is –at least partially– processed like the own (virtual) body ( Kilteni et al, 2012a ). In the immersive virtual training environment, the user may experience the feeling of body ownership over the avatar.…”