A Systematic Review of Techniques, Artifacts, Challenges and Future Directions on Signal Acquisition and Preprocessing in Brain-Computer Interfaces (BCIs)

Recent advancements in Brain-Computer Interface (BCI) technology have enabled new communication paradigms, allowing direct interaction between the human brain and external devices. The effectiveness of BCI systems depends critically on robust signal acquisition and preprocessing techniques for isolating relevant neural activity. This review provides a comprehensive overview of state-of-the-art methods in these foundational areas and classifies BCI modalities according to system design. We examine neural signal artifacts, distinguishing between physiological and extra-physiological sources, and review current mitigation techniques. Through analysis of existing literature, we discuss the strengths and limitations of prevailing approaches and emphasize the role of publicly available datasets. The review concludes by synthesizing key insights and identifying open challenges that continue to shape BCI research.