Because of their genetic make-up, and the Sigma coursing through their viens, the Noodles don't get nightmares or night terrors. They get a mixture of both, which have  unnoficially been dubbed timore recordabor, which is Latin for fear remember. The reason for this is because the overall thing is like a night terror, but with the remembering aspect of a nightmare.

(There actually is a difference between the two, believe it or not. Go look it up if you want, I'm not putting it here because I'm lazy)