Interesting article on sleep disorders
Five disorders that make sleep scary - CNN.com
I was especially interested in this bit on sleep paralysis:
During normal sleep, your brain sends a signal to your body to inhibit your movement while you're dreaming. This keeps you from thrashing around and possibly hurting yourself.But when Sleep Paralysis occurs, the brain either switches on your muscle inhibition feature too soon or doesn't switch it off when you wake up, which can lead to very creepy experiences. In addition to being unable to move, many people will dream while they're awake -- basically hallucinating.
The most common hallucinations that occur with Sleep Paralysis include sensing or seeing another person in the room, being touched, hearing footsteps, floating, or even hearing someone call your name.
First, I wonder if this could explain a lot of ghost sightings. When I was about six, I woke up one night and thought I saw a ghost in my roon. Maybe the above was occuring. (Although, it was many years before I slept with my bedroom door open again.)
Second, there have been many times I've felt like I was touched by someone while in bed or had the classic "falling off a cliff and wake up hitting the bed" scenario. There was one time when I was a teenager I woke up and saw my dad standing next to my bed. Even in that sleep-induced state, though, I could tell it wasn't him: the "person" I saw was wearing a cap, and my dad would never wear a cap inside the house. (Once a Marine, always a Marine.) So I just rolled over and went back to sleep.