I don’t think ”intelligent” is a particularly meaningful concept, and just leads to such confusion as your comment hints at. Do I think a person with locked-in syndrome is still a human being with thoughts, desires and needs? Yes. Do I think we can rank intelligences along an axis where a locked-in person somehow rates lower than a healthy person but higher than a cat? I don’t think so. A cat is very good at being a cat, much better than any human is.