1. Resulting in a Persistent Vegetative State
2. This happened to Barry Crouch Jr.
3. A fate worse then death

You can exist without your soul, you know, as long as your brain and heart are still working. But you'll have no sense of self anymore, no memory, no...anything. There's no chance at all of recovery. You'll just — exist. As an empty shell. And your soul is gone forever... lost. Remus Lupin on the Dementor's Kiss