It's possible for paralysis victims to type and otherwise communicate with the world, but they usually have to do so at a glacial pace. They might not be nearly so limited in the future, though. In experiments combining BrainGate2 (a high-speed neural implant system) with text entry software, researchers had a Lou Gehrig's sufferer type words at six words per minute. While that may not sound quick on the surface, it's incredibly fast for someone relying solely on mental activity to write a message.
The technique could help just about any paralyzed person communicate, but it'd be most useful for "locked-in" patients that have also lost speech. And the performance may get better -- scientists hope to put implants in a part of the brain that could lead to speedier typing. You're a long way from writing a book with your mind, but the necessary technology is now advanced enough that this is no longer a far-fetched idea.
[Image credit: Stanford University/Nature]