Does anyone know the name and cause of the phenomenon where by, just as you are on the verge of falling a sleep you suddenly and sometimes violently jump and are wide awake again ?
I always thought it was called an Alpha Jerk , but I goggled Alpha jerk and all I got was the band !!! so maybe it not that
RORY
[u]Hypnic Jerks[/u] (Edit: This link apparently requires a membership after letting you view it once. Grrr.)
More from [u]Wikipedia[/u].
Ah, yes, the hyp … hypni … hup … hup … myoclonic twitch. Fortunately, there is no band called Myoclonus or Myolconic Twitch (yet).
djm
The late, great Richard Boston, founder of the Campaign for Real Ale (CAMRA) in the UK, once claimed he coined a word to describe the state of being half-way twixt wakefulness and sleep, neither one nor t’other, during which such strange things can happen. His word was “hypnopompic.” You wouldn’t think he’d coined it if you google it. But that was Richard. 
I always feel like it’s some last burst of electrical energy that has to be discharged before sleep can be restful.
In the Deep South (of USA, that is) we called it “catching a possum”, but I suspect that isn’t the medically recognized term.
I kinda go along with that bit of a theory.
I have been known to lie awake all night, with all sorts of thoughts having a rodeo in my head. The vast majority of those thoughts have little, if anything, to do with my day to day living.
I cannot keep up with the ceaseless procession of thoughts, any more than I can remember them once I eventuallly nod off.
A recent sleepless night I do remember was filled with strange and mysterious thoughts about the Polish economy..go figure.
Slan,
D. 
BTW, when all of this is going down..the Nitty Gritty Dirt Band are providing a nice soundtrack..I hear that as well.
D.
This happens to me all too often, especially as of late. I seem to have too many random thoughts for my head to process during the day, so it’s does the bulk of it when I’m trying to get to sleep. I rarely get to sleep before 1am these days. 
Although, I will admit, my random, sleep-preventing thoughts are not punctuated by music provided by the Nitty Gritty Dirt Band
When the head hits the pillow, all fraught and sleep-defying notions may be banished simply by recalling the words of the good Lord himself: sufficient unto the day is the evil thereof. What a wise man! The eejits around him, and the ones who came after him in proselytising mode, were far more stupid.
Steve “rampant-atheist” Shaw 
I’ve always referred to them as “falling dreams” because there’s a sensation of falling when I suddenly jerk awake.
Redwolf
I never knew what that was called, or that it had a proper name, until today. 
Apparently, the falling sensation in particular may be from evolution:
I’ve also heard it described as caused when your astral body is leaving your physical body at the beginning of sleep and suddenly gets jerked back in for some reason. Just saying what I heard. I live in California, after all.
Tony
California Astral Backpressure.
Were they from LA?
I forgot about Napa…nevermind.
“Well I’m caught one more time..up on Cypress Avenue…”
Slan,
D.
I’ve heard that too.
I think the reason there are so many evolutionary and astro-physical theories is because nobody really knows for sure.
I’m happy to say that I experience none of these phenomena. Which is a good thing because I can sleep standing up.
bit trickier for the bipods…
Yeah, but that’s 'cause you’ve got four legs to prop up on. Ever been “tipped”?
I’ve done that twitching thing, but not often. But then I don’t go to sleep very quickly either. I’ve always read in bed before going to sleep since I was a little kid.Gotta have a book, any book if I’m desperate enough. I spend at least an hour or so reading until I finally drop the book. What irritates me is the times that I’m then awake, after being so sleepy, and like Mr. D said, thinking way too much about things that don’t make much sense. But when I wake up, I’ve always got a tune going in my head. Maybe I dream hearing music? Since I so rarely remember any dreams I can’t say, but there are definately tunes going on in there when I wake…
“You know that sensation when you’re sitting up and trying to stay awake, and your head starts dropping and you’re just about to fall asleep, then you jerk yourself back awake? I feel like that all the time.” – Steven Wright