A Personalized Target Placement Optimization Framework for VR-Based Upper Extremity Rehabilitation

Abstract

Featured Application The proposed framework can be directly integrated into existing VR rehabilitation platforms to provide real-time personalized target placement for post-stroke upper extremity therapy, requiring no additional hardware beyond a standard CPU.Abstract Virtual reality (VR)-based rehabilitation is an established modality for upper extremity motor recovery; however, existing systems frequently rely on fixed, random, or therapist-tuned target placement that disregards patient-specific motor capacity and population-level priors. This study proposes a cross-patient collaborative swarm intelligence framework that derives zone-based patient profiles from real VR trajectories and augments them with a similarity-weighted cohort prior distilled from clinically similar patients' successful trajectory clouds and zone-transition graphs. A hybrid Ant Colony Optimization (ACO)-Particle Swarm Optimization (PSO) algorithm optimizes 12 targets per session across a 27-zone (3 & times;3 & times;3) workspace using a five-component fitness function encompassing reachability, zone balance, movement efficiency, heatmap-guided challenge coverage, and swarm-flow consistency. The framework was evaluated retrospectively on a single-center cohort of 36 post-stroke patients and 6373 sessions under a leakage-safe simulation protocol with 70/30 chronological splits; outcomes are model-based proxy success rates derived from each patient's profile rather than directly observed task success. The hybrid strategy achieved a mean simulated success rate of 85.5% +/- 5.5%, a 36.4% relative improvement over random placement (Wilcoxon p<10(-7), Cohen's d=4.91); the leakage-safe split yielded 80.1% on the held-out segment versus 61.1% for random, with no statistically significant train-test gap (p=0.470). Ablation confirmed both PSO and ACO are individually necessary (Delta >= 2.7 pp, p<0.001). Total session-start computation is 78 ms on standard CPU hardware. These findings constitute a proof-of-concept that collaborative personalized swarm optimization can substantially outperform heuristic target placement under in silico evaluation; clinical efficacy in terms of standardized motor outcome measures remains to be established in a prospective randomized controlled trial, and the findings should be replicated across centers, task modes, and a larger cohort before generalization.