Alright Zooby you peaked my interest about something the other day. In the thread where I mentioned driving while sleep deprived, I said that a loud buzzing sound kept waking me up. Now I know that this sound was not externally produced, and you mentioned that TLS's can cause this. So I wanted to explore this issue a bit. I remember when we were talking about my experiences with meditation, that is when I practiced a technique that is supposed to enable astral projection, not that I ever claimed to have left my body mind you, but I did experience something common to other practioners of this form of meditation. I was acutely aware of a deep, deep darkening in my minds eye. I felt and heard an intense rushing with the sensation of extreme upward acceleration. The sound was also pronounced. So first, you seem to feel that this rushing or roaring sound is typical of TLS's? How certain are you that this is an if and only if - iff - bit of logic? In other words, we know that someone having a TLS may hear a rushing sound, how certain are we that this works the other way to a significant degree? If we hear an intense rushing sound we are likely having a TLS? Next, I find the suggestion very interesting [seemingly unlikely] that we might be able to induce a TLS simply by concentrating. I can tell you that my form of meditation mostly involved a focused exclusion of sensory input. The techique is to rid ones mind completely of any external sensation. A strange sense of extreme weight slowly consumes the body as one becomes deeply immersed in this state. It is as if gravity has increased four or five times. Truely! Then, at the deepest level the extreme sense of acceleration came on slowly at first, and then very quickly. Inky blackness seemed to consume my vision even though my eyes were already closed and I was in bed in a dark room. I was then involuntarily catapulted to my feet from a nearly dead- sleep-like state. This was a fear reaction. I was suddenly terrified of what was happening to me. Are any of these sensations also indications of a TLS? I know that my experience is the normal one. This is to be expected but I didn't know this until later. So, if this is a TLS, it is something that apparently most people can learn to do at will. To me that would be quite amazing.