It's smart-ass time again...
(I once had to do some research on that for one of my medical courses.)
I saw a patient with locked-in syndrome once... Horrible. For me, this is one of the worst things that could happen.
Locked-in patients are completely paralyzed except for their vertical eye movement and blinking of the eyelids. They are fully awake and aware with no loss of cognitive functions, but not able to move or to speak.
The patient I know was only able to answer yes/no questions by blinking once for yes and twice for no... And he was only 25. (I know that sounds kind of cruel because being locked-in is terrible not matter how old you are. But locked-in patients have a normal life expectancy... So statictically, there are still 50 years for him to stay in this condition. Horrible.)
Anyway...
Being unable to move after waking up is indeed caused by a normal phenomenon called sleep paralysis. While dreaming in REM phases of sleep, our body is paralyzed so that we cannot perform the movements that are included in our dreams. Rarely, our brain wakes up from a REM state, but the paralysis persists. Like with locked-in syndrome, the person is fully concious, but unable to move for several minutes.
And I have to say I'm lucky to not have experienced it. Sounds creepy... :worried: