Since the 1970's I have been interested in the boundary of being asleep and awake. This state gives rise to hypnagogic and hypnopompic imagery, and gave me the idea for my first UFO book.
Like Pauline, I read a lot of science magazines and one of my favourites is "New Scientist." In the 10 October 2010 issue, number 2729 appeared an article by Laura Spinney which mentions the work of David Dinges, a Psychiatrist at the University of Pennsylvania, Philadelphia.
Dinges is looking at the sleep disorders which occur on the boundary of sleep and being awake. Disorders such as sleep paralysis, hypnagogic imagery, sleep walking, night terrors and narcolepsy, and interestingly for us, alien abductions!
"It is no coincidence he says that alien abductions almost always occur in the recumbent position, in the transition from wakefulness to sleep.'
From my research I can say that it is true that many abduction reports occur at this boundary. I can also say that from my own research working with abductees, that many episodes happen while the individual is lying on their back. I seem to recall that many sleep paralysis episodes are reported when a person is lying on their back, as opposed to lying on their side or stomach. However, much more research needs to be undertaken in this area. It would be helpful if sleep researchers would take the time to study abductions indepth.