Coordinating Challenge and Engagement: A Cross-Domain Virtual Reality Intervention with Adaptive Difficulty for Cognitive and Physical Enhancement in Cognitively Impaired Older Adults

As individuals age, simultaneous declines in cognitive function, physical ability, and visual capacity (e.g., dynamic visual acuity) pose challenges to maintaining functional independence in later life. Despite advances in immersive virtual environments for age-related functional support, dynamic visual acuity remains underexplored, particularly in relation to its interaction with cognitive and motor processes. Meanwhile, existing interventions often rely solely on performance-based difficulty adjustment, neglecting the dual need to maintain engagement and promote skill progression. To address these gaps, we developed the Pareto-based Dynamic Difficulty Adjustment for Cross-domain Co-training in Virtual Reality (CCVR-PDDA) system, integrating psychology paradigm (e.g., Stroop task), upper-limb motor training (e.g., arm lifting and raising), and dynamic visual exercises (e.g., multi-directional eye movements). A 12-week longitudinal study involving 60 older adults (≥65 years) demonstrated significant cognitive improvements, sustained at six-month follow-up. Qualitative feedback further supported the system's usability, motivation enhancement, and long-term engagement potential. These findings underscore the efficacy and acceptability of CCVR-PDDA in promoting cognitive health in aging populations.