BCI4ALL aims to research and develop effective EEG-based brain–computer interfaces (BCIs) for individuals in locked-in state (LIS) and completely locked-in state (CLIS). The project explores machine learning techniques to improve BCI usability, the use of transcranial direct current stimulation (tDCS) for neuromodulation, and LLM-based communication support. The developed approaches are also expected to contribute to the assessment and monitoring of patients with disorders of consciousness (DoC).