I think that is hypnagogia. http://en.wikipedia.org/wiki/Hypnagogia http://en.wikipedia.org/wiki/Hypnagogia. And it doesn't necessarily require environmental no

I think that is hypnagogia. http://en.wikipedia.org/wiki/Hypnagogia http://en.wikipedia.org/wiki/Hypnagogia. And it doesn't necessarily require environmental noise to be triggered. There's a lot of material out there on it being linked to lucid dreaming.