Yep. I have this. 99.9% of the time it happens when I'm asleep or drifting off to sleep or just waking up (especially in the early morning). And I also think that they can be worse when I've over-exerted. I've spent quite a bit of time trying to figure out what causes this without any luck. I suspect that there's not just one root cause. Even a couple of neurologists that I've seen have never heard of this except one who said, "It's just anxiety..." No, it's not just anxiety...
I've noticed that when I experience these vibrations, they seem to centered around my diaphragm. In fact, very often it feels like my diaphragm has tightened up and it's every so slightly more difficult for me to breath. I have had problems with reflux in the past and I do have a hiatal hernia. I also know that some alternative practitioners believe that hiatal hernias are more serious than they're given credit for. And since the vagus nerve passes right through that area, hiatal hernias can result in a number of odd symptoms. So I developed a theory that (at least in my case), the hiatal hernia or the acid reflux was irritating the vagus nerve resulting in this feeling of tremors. Why this seems to happen only during sleep onset I can't explain. Maybe it has something to do with whatever the nervous system is doing during sleep phase transition. As one of the top sleep neurologists in the country once said to me, "Lots of weird stuff happens during sleep." Not very helpful.
Since I had a feeling that this might be related to reflux and or general GI problems, I went to see a gastroenterologist at Mass General hospital in Boston. One of the top centers for gastroenterology. I really was going only to see how bad my reflux was. The doctor took my history and asked if there were any other symptoms I wanted to tell him about. So I figured what the heck and told him about my "vibrations." I almost fainted or cried (or both) when he said, "Oh yeah, I know what that is." He called it "visceral hypersensitivity" which is a neurological condition in which nerves associated various organs become overly sensitive. After some testing it was determined that my acid reflux was actually extremely minor which he said confirmed his suspicion about VH. He said that no one knows why this happens. His treatment is to use low doses of different nueromodulators like gabapentin or amitriptylene and also acid blockers. I didn't want to try any of these, but the vibrations were really ruining my quality of life. So right now, I'm on 300mg of gabapentin and 20mg of amitriptylene. Both help me to sleep and they definitely reduce the intensity of the vibrations. These are not drugs I really wanted to take (I'm very anti-pharma), but I didn't think I had a choice at this point.
If you Google for "sleep vibrations" or "sleep tremors" you'll come up with a surprising number of hits. I've been participating in a thread that has been active for the last 10 years. You can find it here if you're interested:
https://www.medhelp.org/posts/Sleep-Disorders/tremors-during-sleep/show/476754. Towards the end, you'll see some posts of mine with information that I've learned here.
So far, there's some commonality among the folks I've spoken with. Most of them had this happen after some illness/infection. Many of them definitely had GI problems/gut dysbiosis. So I suspect that this is a neurological condition brought on by some sort of nutritional deficiency. As many of you may know, lack of certain B vitamins can cause neurological issues. Maybe this is one of those issues. In my case, I recently discovered that I was very low in most of the B vitamins and I definitely have some GI problems.
Sorry for the long post, but I'm hoping that this level of detail will be helpful to those looking for solutions to this problem.
