HMD-VR Training for Confined-Space Operations: Evaluating Performance and Cognitive Demand in Real-World Execution

Training for confined-space operations presents significant challenges due to safety risks, limited accessibility, and the complexity of reproducing realistic conditions. Within this context, immersive technologies such as Head-Mounted Display Virtual Reality (HMD-VR) offer a promising alternative for procedural training. This study evaluates the effectiveness of a hands-free, bimanual HMD-VR training system for confined-space operations as an alternative to physical training when access to real environments is constrained. Two HMD-VR configurations were investigated and compared with a physical training condition using a shared multi-step procedural scenario. Training outcomes were assessed across repeated executions and through a real-world evaluation, focusing on procedural performance and cognitive demand. Results show that all groups achieved significant improvements in performance over repeated executions, with reductions in completion time and error rate. Importantly, no statistically significant differences were observed between groups during the final real-world evaluation, and non-inferiority analyses confirmed that HMD-VR training did not result in performance outcomes worse than those achieved through physical training within predefined operational margins. Similarly, no significant differences emerged in either EEG-derived Cognitive Load (CL) or subjective workload at the final execution, despite a reduction in perceived workload over time. Analysis of subjective immersive experience revealed consistently high levels of presence and engagement across HMD-VR conditions, with no significant differences between configurations. However, spatial presence and perceived realism decreased over repeated exposure, suggesting an adaptation effect rather than a continuous increase in immersion. Overall, the findings indicate that, under the controlled conditions of this study, HMD-VR training enables real-world procedural execution and cognitive demand profiles comparable to those observed following physical training. These results support the potential of HMD-VR as a viable approach for novice procedural training in confined-space operations, particularly in contexts where traditional training is limited by safety, cost, or accessibility constraints.