This study validates a virtual-reality adaptation of the Color Trails Test that integrates full-arm motor actions with cognitive demands and finds that people with Parkinson's are slower, less accurate, and show altered kinematics (longer head-hand delays, lower peak velocities) compared with…

The VR-CTT provides an ecologically valid, quantitative platform with motor-cognitive and kinematic endpoints useful as sensitive outcome measures and a potential rehabilitation/training tool in PD, though it does not address molecular mechanisms or direct therapeutic targets.

Cognitive impairments in Parkinson's disease (PD) often emerge alongside motor symptoms, yet most clinical assessments examine these domains separately. This mixed-design study explores the utility of a virtual reality-based Color Trails Test (VR-CTT) as an integrated, immersive tool to assess motor-cognitive interaction in PD. Twenty-three individuals with PD (ON medication) and twenty-three age- and education-matched healthy controls completed both the standard pen-and-paper CTT and the VR-CTT, which preserves the same cognitive demands while introducing an upper-limb motor component through full-arm reaching to virtual targets. As expected, individuals with PD were slower and less accurate across both formats. However, we observed only moderate-to-low correlations between completion times in the two CTTs, thus suggesting that the VR-CTT may capture distinct and ecologically valid aspects of motor-cognitive performance. Indeed, kinematic analysis revealed longer head-hand coordination delays and reduced maximal execution velocities in PD, pointing to subtle, yet specific motor difficulties during cognitive tasks. Beyond confirming feasibility, these results highlight the VR-CTT's potential as a novel tool for identifying motor-cognitive dysfunction and informing targeted rehabilitation strategies. Its immersive nature and multi-competency format position it as a promising intervention platform for cognitive-motor training in PD and related disorders.