Age-related changes in movement control in virtual reality: a Fitts’ task protocol

Abstract

Preserving motor and cognitive function in older adulthood is a central challenge for healthy aging and rehabilitation. Immersive virtual reality (VR) systems have emerged as promising tools to address this challenge, with many applications requiring users to perform targeted reaching movements toward virtual objects. Previous research suggests that aiming movements performed in immersive VR differ substantially from those executed in real-world settings, likely due to alterations in the multisensory information available for movement control. This is particularly relevant for older adults who experience changes in sensorimotor integration and slowing in information processing, which may make them more sensitive to altered sensory conditions. Despite the growing use of reaching tasks in VR, movement control during speed- and accuracy-constrained aiming in immersive contexts has not been systematically examined in older adults. Moreover, while augmented feedback is typically provided in VR reaching tasks, its implementation varies widely across the available studies. This limits our understanding of how different task and feedback conditions influence performance and the underlying sensorimotor control mechanisms in VR. To address this gap, we propose to examine the ability of healthy older adults (65–75 years) to perform Fitts’ task–a well-established, accuracy-constrained reaching paradigm–in immersive VR, in comparison with younger adults (18–28 years). To do so, task difficulty will be manipulated through target size to systematically impose varying accuracy constraints, thereby modulating cognitive control demands. Meanwhile, biomechanical constraints and VR-inherent perceptual factors, such as visual distortions and altered depth cues, will be held constant. Further, augmented feedback conditions will be varied to determine the best way to support accurate motor execution. The proposed protocol aims to provide a methodological benchmark for systematically evaluating motor performance in immersive VR and to support comparisons across populations and task conditions. The findings furthermore can inform the design of VR-based training and rehabilitation solutions for upper limb movements that aim to engage motor-cognitive processes in older adults.