## 4 Discussion
### Limitations and Directions of Further Studies
As technology advances, ethical guidelines and regulatory frameworks may struggle to keep up, creating risks of misuse or exploitation of VR-BCI capabilities in ways that are not yet fully understood. Key considerations for successful BCI-VR integration:  
1. Signal Quality: A primary challenge in BCI research is obtaining high-quality, reliable brain signals. Factors such as electrode placement, signal interference, and individual neurophysiological variations can significantly impact signal fidelity, which is crucial for accurate decoding and control. Advancements in sensor technologies, signal processing algorithms, and personalized calibration methods are necessary to improve signal quality and robustness [86]. 2. User Training: Effective control of BCI systems often requires extensive training and learning for users to develop the necessary cognitive skills and mental strategies. The ability to modulate specific brain activity patterns, such as steady-state visual evoked potentials or motor imagery, can be highly individual and needs to be cultivated through dedicated practice and feedback. Developing user-friendly training protocols and adaptive learning algorithms is crucial for enhancing BCI control and accessibility [87]. 3. Ethical Considerations: The integration of BCI technology into virtual environments and personal devices raises important ethical concerns that require careful consideration. Issues of privacy, data security, and informed consent must be addressed to ensure the responsible and ethical development and deployment of these systems. Additionally, potential risks, such as unintended cognitive or neural impacts, should be thoroughly investigated and mitigated to protect the well-being of BCI users [88; 89]. The inclusion of visual aids such as comparison tables, system architecture diagrams, and interaction diagrams can greatly simplify complex information in a VR-BCI system. Comparison tables can help to quickly distinguish between different system components, technologies, or approaches, highlighting their relative strengths and limitations side by side. This will enable users to understand complex trade-offs and decision points at a glance, reducing the cognitive load associated with the text. System architecture diagrams offer an overview of the VR-BCI structure, illustrating the relationships and data flow between hardware, software, and user input, helping to clarify how each part contributes to the functionality of the system. These diagrams make it easier for non-technical stakeholders to understand the structure and flow of the system, improving interdisciplinary communication. On the other hand, interaction diagrams provide a step-by-step visualization of user interactions with the system, which can simplify understanding of the user journey and potential bottlenecks or error points. By mapping user actions and system reactions, flowcharts facilitate a better understanding of system processes and user experience design issues. Together, these visual aids allow team members to engage more intuitively with intricate details, fostering faster understanding and more informed decision-making. Thus, the aforementioned visualizations bridge gaps in understanding between different teams. Despite these challenges, the future of commercially available BCI-VR solutions appears promising. As technology advances and costs decrease, we can expect to see more widespread adoption of these integrated systems in various fields, including healthcare, gaming, and education.