Hello, Unfortunately for physicians shaking is a very vague term and it could mean many different kinds of movements, ranging from tremulousness of the body, to flailing, to arrhythmic shaking to rhythmic shaking and all have very different implications. However, I will given you the most common cause of what you saw. Most likely what occurred is called convulsive syncope which means that when you pass out you have some jerking movements, but it is not considered a seizure. What happens is that blood flow is disrupted to the brain and the person loses consciousness. Because the nerve cells are suddenly deprived of oxygen, they fire abnormally for a few times causing body jerking, but when the person collapses blood flow is restored and the movements stop. So essentially the movements are caused by passing out and not by a seizure. Likely what happened also was what we call a vasovagal reactiong in which due to stress, emotional response among other things, the blood vessels dilate and blood rushed down from the head into the legs causing a person to pass out. The classic example of this is when a person who is getting their blood drawn passes out. It is not considered abnormal, and can happen to anybody. Lastly, just to describe what a true seizure looks like. Typically what happens is that a person will first stiffen up, the eyes will turn up into the head with the eyes remaining open. There is often a very loud scream due to the abdominal muscles tensing up and expelling air from the lungs. The stiffening phase is then followed by a rhythmic, whole body shaking. When I say rhythmic I mean that the jerks occur at regular intervals and at the same time in all extremities of the body. The gradually slow down and the person becomes limp and often is breathing very hard.When they wake up there is almost always confusion that lasts several minutes and then slowly the person returns to their normal state of mind. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Janne Kristoffer Nissinen, Neurologist