A Review of Strategies for Deploying Stage of Disease-Based Brain-Computer Interfaces for Communicative Functional Substitution in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterised by a gradual loss of motor function and communication. Brain-computer interfaces (BCI), as an alternative means of communication without the need for muscle control, have demonstrated a unique potential for applicability in different disease stages of ALS. In this paper, we propose a set of BCI deployment strategies that match the disease stage based on the King clinical staging system, the MiToS functional staging system, and the evolutionary pathway of communication ability. In the early stage of the disease, when the patients visual and attentional functions are still good, it is recommended to deploy non-invasive BCI systems, such as SSVEP and P300, because of their low training burden and high recognition efficiency. Priority is given to highly robust BCI paradigms that do not require active cooperation, such as trained auditory/tactile P300 systems, or implantable cortical systems to maintain residual communication abilities. This review emphasises that BCI training should be initiated as early as possible in ALSs early to middle stages to build a stable decoding model and lay the foundation for effective communication later. Future development of BCI should focus on stage adaptation, deployment feasibility and system durability improvement.