A few years ago, I noticed something strange as I tried to fall asleep: Just as I was about to reach a deep slumber, my muscles would twitch. Each night, it would happen a few times, never in the same area, until I finally fell asleep. I didn’t think much of it, and it even went away for a year or two. Recently, though, the twitching has returned. This time, I felt like I needed to get the final answer. So I did what any health reporter would do: I skipped the doctor and went straight for the medical literature.