PVS is a shamefully hopeless diagnosis. It is one where the doctor decides there is nothing he can do, and so gives himself permission to give up trying.
I am more encouraged by the doctors who understand that there are stages of consciousness, and that we can be unconscious for a while, then emerge from it, and sometimes retreat back into it, only to (oftentimes) re-emerge.
I detest when they refer to PVS as a permanent condition. Only death is permanent.