Around the world, 15 million people suffer from a stroke every year, and one-third are permanently disabled. In the EU, the number of strokes is increasing, from 1.1 million per year in 2000 to more than 1.5 million by 2025. After a stroke, 70% of survivors have deficits in hand function, and 40% are unable to use one hand in the long term. How can we improve rehabilitation after stroke using brain-computer interface technologies?