I think that the NDE must have become more widely known thanks to Dr Moody in the 70s. There have been reports of OBEs going back through recorded histories for a long, long time or experiences that sound like them.

Trying to read information about them is difficult .. I like to read from both sides. I now the experience the person had that I mentioned yesterday is true. It wasn't anything spectacular .. just a separation of consciousness from the body and a desire to get back which he did quickly. The nurse that was with him at the time understood what had happened. They have managed to create a form of OBE in the lab now

http://news.bbc.co.uk/1/hi/health/6960612.stm

Now that it's become so public it's not going to be harder to find out what is real and what isn't. I doubt if we'll ever find out what the truth is regarding this