Hi,
The following is a general response which I posted to another thread which may throw some light on your condition and may give you some measures to try which may be of help.
I suffer from an un-diagnosed sleep condition (for more than a decade now) which manifests itself in a variety of ways. One of the ways it manifests is in the form of a type of hypnic jerks similar to what many people describe in this thread. For me these tend to occur later in the night, after sleeping for a few hours, and may then continue to the morning. They involve jolting awake from dreamless sleep for no apparent reason. As and where they occur repeatedly they are major sleep disruptor. Another way my condition presents is in the form of more traumatic waking episodes whereupon I become partly awake or aware with an intense feeling of something being very wrong (like I'm not breathing or I’m simply dying) and struggle desperately, in a panic, to wake fully…not pleasant!
I've had this all checked out with various sleep studies, tests, etc. Although, the sleep studies have confirmed that the episodes are real, they’ve ruled out all the various medically recognised sleep conditions including sleep apnoea. In fact, all the tests have showed that I’m in good physical health and condition. Moreover, I exercise frequently and I am near ideal weight. I have suffered in the past from anxiety but I’ve been relatively stress and anxiety free for some years now. I am male and in my late forties.
However, in spite of the lack of any medical diagnosis, the good news is that I have this condition largely under control. I have achieved this primarily through my diet. To make a long story short, I have discovered, formally by chance, latterly through research, that the following dietary approaches provide a means to greatly reduce the symptoms (and probably the cause of) my condition.
These approaches are, in order of effectiveness; A) A gluten free diet, B) the Paleo diet and C) The AIP (Auto Immune Protocol) diet.
If you check these out, you’ll see that these diets, A to C, get progressively more stringent (the AIP diet in particular is pretty difficult and time consuming to follow, but is very healthy and has lots of additional health rewards). Whichever way, I find that the more I stick to the AIP diet the less symptoms I get and the better I sleep….essentially a real life changer for me.
Notwithstanding, the need to rule out more obvious, possibly dangerous, sleep conditions, such as sleep apnoea (with a medical professional), I would suggest anyone suffering from hypnic jerks or other similar undiagnosed sleep conditions could try the dietary approach as described above. That is, try first a gluten free diet (without processed substitutes), then if needs be try the Paleo diet and/or then the AIP diet. In spite of what some mainstream medical professionals might advise, these diets are perfectly healthy and nutritionally balanced. However, they do take some effort but if it helps in any way with the debilitating sleep issues described in this thread then they can only be well worth the effort.
If you’re curious as to why these dietary approaches might work, you can check out the research and thinking behind the Paleo and AIP diets on line or in various books which you can find in the health section of good book stores (essentially, I believe that I have some sort of gut related autoimmune condition which manifests itself in sleep disturbance).
Hope this is of some help. P.