Intelligence Amplification and Recovery from Severe Brain Damage
If I remember correctly, one of the characters in Marooned in Realtime by Vernor Vinge said that he knew somone who was almost decorticate but was able to lead a partly-normal life by intelligence amplification. You can think of this as a matter of artificial intelligence acting as a substitute for the natural kind.
One potential problem with using intelligence amplification as a means of recovery from severe brain damage is that the patient might not be the same person as before the injury. (For example, putting a robot head on a beheaded corpse would not count as recovery.) On the other hand, it looks like the lower parts of the brain have enough ability to learn (seen via Winds of Change) to retain parts of the original personality.
Another potential objection is that some people might object to being kept alive by such artificial means. (You can think of this as the other “yuck” factor.) This is far more general than objecting to a one particular technology such as, for example, embryonic stem cells. The only answer I have is: I am not responsible for those people. As Ann Coulter put it:
On the bright side, after two weeks of TV coverage of the Terri Schiavo case, I think we have almost all liberals in America on record saying we can pull the plug on them.
Addendum: The exact quote (from the end of Chapter 18) was:
"You know, we had a mascot: a poor, sweet girl, close to anencephalic. Even with prosthesis she was scarcely brighter than you or I. Most of the time she was happy." The expression on his face was wistful, puzzled. "And most of the time, I am happy, too."A review with the quote can be found here.