Is virtual fear torture?

I was reading a book on the future of biotechnology and ethics.  There was a story that brought to mind a slightly different example of my own that I was wondering about.  After 9/11 there was a huge debate about whether waterboarding is torture.  What makes it a serious interrogation technique is that it makes you feel like you are going to drown (die).  If you are confident that the CIA wouldn’t really kill you, I think it loses some of its effectiveness.  Probably still painful (not that I have ever experienced it myself), but not intensely like electroshock or pulling out fingernails.  

So what if instead of waterboarding we invent some kind of electrode insert that makes you think you are going to die?  That's all it does.  It would be totally imaginary and artificial, but the “subject” wouldn’t know that.  Assuming it was really convincing, would that make it as much torture as waterboarding is, even though there is no pain (real or imaginary) – just the fear that you are going to die?