Crafting Usability in Neuro-Narrative Games: The Joint Influence of Imagery Perspectives and Task Sequences in BCI-VR System

Neuro-narrative games represent an emerging integration of brain-computer interface (BCI) and virtual reality (VR) technologies, leveraging imagery perspective and motor imagery (MI) task sequence as two critical design factors. However, the individual and combined influences of these factors on system usability remain underexplored, especially regarding the interaction between first- and third-person perspectives and the structuring of MI task sequences. This paper presents a unified evaluation framework that combines objective electroencephalogram (EEG)-based usability metrics with subjective user feedback to provide a comprehensive assessment in a custom-designed, user-centered BCI-VR narrative game system. Employing a within-subject experimental design, we systematically examine the main and interaction effects of perspective and sequence structure, revealing that immersive VR can mitigate perspective-induced usability gaps and that fixed MI sequences reduce cognitive workload and enhance user performance. Conversely, mixed task sequences boost user motivation but lead to increased mental workload. These findings contribute actionable design guidelines for expanding accessible, engaging, and user-centered BCI-VR game experiences to a broader range of users, ultimately supporting the development of more effective neuro-narrative systems. Importantly, our approach bridges objective neural data with subjective user experience, paving the way for holistic usability evaluation in future BCI-VR applications.