Is it comparable to someone braindeath who's body is kept alive artificially, would she cramp too if the machines where shut down?
Well, the only times I've ever seen it, the individuals were brain dead
on active life support (in their case, ventilators). I do recall one young guy without any type of external support who was brain dead and postured a lot; he had been struck by lightning and pretty much had his circuits fried.
I honestly can't recall being at bedside with anyone who had 'life support' discontinued. Any posturing or muscle tone probably just relaxes and goes limp.
In this grainy video of the execution of Karl Frank in Prague in 1946 there is an inward movement of the left hand and arm after the drop; is that an example of decorticate posturing ?
Sorta.
I think that's just a post-mortem twitch or jerk; in an instant death like that I'm sure there's a spasm or two.
Whereas in posturing with brain death-- decerebrate or decorticate-- the muscles are held with a lot of "tone." It's really like a rigidity; if you pulled against it, you probably couldn't completely straighten the extremity out.
Source: I'm not an expert by any means, but I've done plenty of bedside nursing on dying and brain-dead patients.