Monday, February 4, 2013

Sleep, perception and reality

When I was in the rehab facility in the UK, I began to get annoyed at how often my sleep was being disturbed. At the time, I was a falling risk, which included the possibility that I might fall out of bed and be unable to get up off the floor. Never mind that I hadn't fallen out of bed for over thirty years, or that I knew how to get up, with great difficulty, but I could do it; I was a falling risk, so a carer came and checked on me every hour.

Normally, this wouldn't have been a problem, since they would open the door quietly, check that I was still snoozing, and begone. My left eye, however, didn't close properly, and still doesn't: the lower lid doesn't work yet. So the carer could be as quiet as you like, but the room would suddenly brighten for a moment. My brain would perceive the light, and wake me up, just as the carer closed the door and went on their merry way, oblivious to having woken me up.

Eventually, I managed to get them to leave me alone, and then moved down to Dorset where my room was quiet and dark all night, but I discovered that I was sleeping less than I had before the stroke. This is sufficiently unusual post-stroke that I was surprised, and initially skeptical but it seemed that, independently of how tired I got, I actually slept less.

I suspected that how grumpy I felt after a 'bad' night's sleep did not necessarily correlate with the actual quality of rest, or whether I slept enough. Being a fan of science (or a giant nerd, take your pick), I decided to test this using "Sleep as Android" to provide a third party opinion on how soundly I slumbered. The app had the added benefit of recording any noise made, so I would also find out if losing weight meant that I snored less, and whether I talked in my sleep, which would be an exciting new brain damage development.

The data demonstrate, to my satisfaction, that it's possible to get a good night's sleep, but have such a strong memory of being awake, that I feel as though I slept poorly, and am grouchy. The converse is not true: I never think that I slept well, when I did not. Also, the snoring and accompanying apnoea are gone (yay!), and I am not a chatty napper (boo?).

At the same time as I formulated my hypothesis, the notion of a "second sleep" was doing the rounds. For all I know, it's been debunked, but it coincided with my discovery that I tend to zonk out completely for 3-4 hours, wake up for a bit, then go back to sleep more or less soundly. If I try to sleep more when I wake up, it doesn't work, and I end up sleeping less on balance. If, instead, I get up, go to the bathroom, read a bit, check email, and go back to bed, all within about half an hour, no more than an hour, then I sleep well for my second sleep.

TL;DR: My sleep patterns are weird, but not as weird as mischaracterizing sleep that was good as being bad on the basis of short-term memory. If you're grouchy from bad sleep, make sure you're actually sleeping poorly with a cunning machine. Also, I don't snore, boys.