I do personal experiments in that all of the time. When I wake
   up, I first try to decipher the dream I just had very quickly so
   that I don't forget it. I do that by linking up things I talked
   about or thought about the last awake period to the dream. I can
   always link stuff together but it's always in metaphor, symbolic
   forms in the dream. But I only have a few minutes before the
   dream fades. By linking up the dream to the prior awake period,
   all that is left is accounting for the gap in time when I left.
   For that, alas, I have to look at a clock. I'm still trying to
   figure out that one. Might be impossible... but I' keep at it
   now and again.