NPR’s Fresh Air interviews  sleep disorder specialist and neurologist Guy Leschziner.

On what we know about recall after a sleepwalking episode

We used to think that people don’t really remember anything that occurs in this stage. That seems to relate to the fact that the brain in parts is in very deep sleep whilst in other parts is awake. What we have learned over the last few years is that actually quite a lot of people have some sort of limited recall. They don’t necessarily remember the details of all the events or indeed the entirety of the event, but sometimes they do experience little snippets. … On one occasion, [a patient] dragged his girlfriend out of bed in the middle of the night because he thought that a tsunami was about to wash them away, and those kinds of events with strong emotional context are often better remembered.