No fair to keep answering questions after I said I was leaving!
Just kidding, I'm happy to answer questions, I just feel silly now.
Somatoparaphrenia is caused by a stroke and patients deny that certain body parts belong to them.
Somatoparaphrenia - Wikipedia, the free encyclopedia
The "monothematic delusion" part is quite interesting. It means that the patient is otherwise perfectly intelligent and rational.
Ramachandran is hypothesizing that BIID would be a kind of congenital somatoparaphrenia. I say "congenital" because (also in answer to another question of yours) people with BIID have memories of their desires going back to very early childhood. That indicates that it's not brain damage but more of an irregularity of the circuitry of the brain. As for me, it started when I was about 5 years old (or at least, my first memory of it dates back to that time). I used to pretend I was "crippled" all the time. When I played house with my friends I always wanted to be in a wheelchair and they would get exasperated with me because we didn't HAVE a wheelchair to play with, and besides, they didn't see what was so fun about that. lol
The VCS didn't last for 24 hours, just the effects of it did. For 24 hours I experienced a marked lessening in the desire to be paraplegic. Someone with somatoparaphrenia will actually admit that they "own" their disowned body parts for about 24 hours after VCS and then they will revert to denying it. So, basically the VCS is not used to actually cure the condition but to verify the location and nature of the irregularity. I am not quite ready to say that it "worked", because I was extremely ill for much of that time, and one could guess that I was simply too ill to think much about anything else. But if Ramachandran's research finds that the vast majority of BIID sufferers also experience what I experienced that could be proof that his hypothesis is correct. We'll have to wait and see on that one, as the study is ongoing.
FWIW, I was forewarned of the effects of VCS and I went willingly to this study, spending a great deal of money to get myself to California, and ended up retching miserably into a bucket in the lab and feeling just about as awful as I ever have in my life. If that's not proof of a desire and willingness to find treatment for this condition, then I don't know what is. *shrug*