One thing you might try is to write your thoughts on paper but not use any flashlight or any other light. The light may be more disruptive to both your sleep and your wife's than the movements. I sometimes capture thoughts by writing in the dark. There may be a tiny bit of light so I can see whether I'm writing on top of other writing, or I might just go by feel to know what part of the page I'm on and remember where I've written. I usually write just one or two words for each idea. Sometimes I space them too far apart (using up paper; that's OK since I'll likely erase and re-use it) or rarely I've written two things on top of each other.
You can try to store your paper closer to your bed so you can just reach over and get it without rolling over: possibly keeping it under your pillow or on the far side of your pillow, or modifying the furniture so there's a shelf or table within reach (designed to avoid bumping your head, though).
I guess recently my strategy has been to either just fall asleep, or use mnemonics. I like books like "The Memory Book" by Jerry Lucas and Harry Lorrayne, or "A Sheep Falls Out of A Tree" by Christiane Stenger, which teach mnemonic techniques. Here's an idea I just thought of: each evening before falling asleep, draw a picture on a pad of paper or put a picture or object or book beside your bed -- a different one each time; something giving an interesting visual image. Then, when you think of ideas while falling asleep, connect them in your mind to that image. For example, if it's an image of a lion, and the idea is "must remember to bring that report with me when I go to work", you could imagine yourself sitting on the lion's back and spreading the report out across the lion's back with difficulty while the lion moves around wildly. The more ridiculous the image, the easier it will be to remember. If you use a fiction book you know well as the anchor, you could connect different ideas to different scenes in the book.
I like to distinguish between active memory and passive memory. Active memory is like "I must remember to do that." Passive memory is like "I know that person's phone number". Passive memory doesn't bother you -- it doesn't prevent you from having a mind like water. So as soon as you've memorized something adequately so that you're confident that when you look at the picture of the lion in the morning you'll be able to remember it, then the thought won't keep you awake.
You might like the book "Insomniac" by Gayle Greene. Tryptophan, 5-hydroxy-tryptophan (5HTP) or melatonin can help people fall asleep. I think aerobic exercise can help raise low blood pressure.
Last edited by cwoodgold; 12-23-2012 at 08:05 PM.
Reason: Added a paragraph
Inability is an abstract thing involving comparison with alternate universes; it cannot be experienced.