This doesn't answer your question but nevertheless:
Do you know what Bergman did once? He had Liv Ullmann trying to sleep and there was the very subtle sound of a clock (vivible by the side of the bed). Then when he wanted us to know she slept he simply took away the sound of the clock. He brought it back a bit later to tell us she was awake again. Very simple, very elegant, very effective. But then, Bergman is Bergman. The rest are just filmmakers.
Very cool tidbit. I take it the camera was focused on her the whole time, and the only subtle change was the clock sound falling off and then rising again.
That's the kind of light touch that separate the greats in every medium, eh?
G